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Sabtu, 10 Januari 2009

Who should recondition my seals?

Such a question often comes up when it is time to recondition a mechanical seal: We use several different brands of mechanical seals in my plant. When a pump is taken out of service, we usually send the seal back to the original seal manufacturer for reconditioning. One of my suppliers has offered to recondition all of my seals, regardless of brand. Is this a good idea?

Most process plant maintenance departments return their used mechanical seals to the original seal manufacturer (or Seal OEM) for reconditioning. Because the cost for a rebuilt seal is usually only about half the cost of a new seal, this is an effective way of saving money instead of buying new seals for every pump overhaul.

The Seal OEM's service center strips the seal down to its individual components, checks each against original equipment drawings and specifications, and identifies which parts need to be replaced and which can be cleaned and refurbished. They then rebuild the seal to like-new specifications using the same assembly equipment as a new seal and performing the same final quality checks with the same test equipment.

In most cases, the Seal OEM returns the original seal. Some Seal OEMs operate an exchange program where you will receive a reconditioned seal previously used by a different customer, much like returning the "core" and buying a rebuilt alternator for your car. In either case, you can expect the seal to perform just as it would if it were new. It is usually covered with the Seal OEM's warranty, just like a new seal.

The major Seal OEMs have always taken the position that refurbishing another manufacturer's product is a risky venture for reasons related to product liability, emissions, safety and maintaining a good reputation with the customer. When someone other than a Seal OEM attempts to recondition a seal, it can be even riskier.

From your point of view, consider the following:
Lack of Application Information

Most Seal OEMs provide their customers with an observation report describing the condition of the seal when returned. Sometimes this is expanded to include a complete failure report. To do this effectively, the repair people need to know the application details (pumped product, concentration, viscosity, temperature, pressure, operating conditions, etc.), which the Seal OEM will have on file from his original engineering selection. It may be difficult for the non-OEM repair shop to make meaningful conclusions without knowing the particulars of the application. If you are accustomed to your Seal OEM providing failure/observation reports, you may lose this ability with a non-OEM shop.
Material Identification

There are several critical components in any seal, particularly the carbon-graphite and carbide faces and the elastomers. Carbon-graphite all looks the same, but dozens of different grades exist. Many are proprietary to certain manufacturers, specially formulated to produce specific corrosion, thermal or tribological properties. It is practically impossible to determine the grade of a piece of carbon-graphite through testing. Unless you get lucky, most substitutes will not perform the same way as the original material, especially in challenging applications. The same issues apply to silicon carbides, tungsten carbides, elastomer O-rings, etc.
Material Equivalency

Even if the non-OEM repair shop can identify the Seal OEM's proprietary material grade from a drawing, they will have to substitute another grade because the original is proprietary. Changing carbon-graphite, carbide face material or an elastomer compound can negatively affect performance.
Dimensional Tolerances

Each individual component in a mechanical seal typically has two or three critical, tight tolerance dimensions. Usually these close tolerances are necessary to ensure the parts are round, concentric, perpendicular, free to move relative to one another without binding, and/or have the correct shrink or press fits. Any

components replaced by the non-OEM repair shop will likely be measured and reverse-engineered. There is a high probability the dimensions and tolerances will not be identical to the Seal OEM parts, particularly if the worn parts were abraded, corroded or broken-making accurate measurement difficult. This may significantly affect seal performance.
Sealants/Lubricants

Some mechanical seals are assembled with sealants or lubricants to improve performance during the start-up and break-in period. It is unlikely the non-OEM repair shop will be aware of this, as these notes are in factory assembly procedures and seldom appear on the top assembly drawings sent to customers. Obviously, performance of the seal could be negatively affected if a necessary sealant or lubricant is omitted during assembly.
Assembly Procedures

Mechanical seals (especially dual seal arrangements, metal bellows seals and dry gas seals) can be tricky to assemble. They may need special fixtures or tooling to ensure press-fits are square and true, O-rings are not cut or abraded, drive pins are correctly aligned, etc. Some seals require heat cycling at different stages of assembly to relieve stresses. Lapping specifications and finishes are not the same for all seals. The non-OEM repair shop will not have access to the fixture designs, specifications or procedures required to ensure proper final assembly of complex arrangements.
Conclusion

You ultimately choose whether you send your used seals to the Seal OEM or to a non-OEM repair shop. Price and delivery obviously enter into the decision process. The trade-off, however, could turn out to be lower seal reliability and higher safety and environmental risk.

Next Month: How will the new P3-A centrifugal pump standard affect you?

We invite your questions on sealing issues and will provide best efforts answers based on FSA publications.
Fluid Sealing Association

Sealing Sense is produced by the Fluid Sealing Association as part of our commitment to industry consensus technical education for pump users, contractors, distributors, OEMs and reps. This month's Sealing Sense was prepared by FSA Member Rick Page. As a source of technical information on sealing systems and devices, and in cooperation with the European Sealing Association, the FSA also supports development of harmonized standards in all areas of fluid sealing technology. The education is provided in the public interest to enable a balanced assessment of the most effective solutions to pump technology issues on rational Total Life Cycle Cost (LCC) principles.

The Mechanical Seal Division of the FSA is one of six with a specific product technology focus. As part of their educational mission they develop publications such as the Mechanical Seal Handbook, a primer intended to complement the more detailed manufacturer's documents produced by the member companies. This handbook served as the basis for joint development of the more comprehensive Hydraulic Institute publication: Mechanical Seals for Pumps: Application Guidelines. Joint FSA/ESA publications such as the Seal Forum, a series of case studies in pump performance, are another example as is the Life Cycle Cost Estimator, a web-based software tool for determination of pump seal total Life Cycle Costs. The Sealing Systems Matter initiative also was launched to support the case for choosing mechanical seals that optimize life cycle cost, safety and environmental compliance.
source :http://www.maintenanceworld.com/Articles/pumpzon/recondition-seals.html

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Micrometer : Types

Basic types
The image shows three common types of micrometers; the names are based on their application:

* Outside micrometer (aka micrometer caliper), typically used to measure wires, spheres, shafts and blocks.

* Inside micrometer, used to measure the diameter of holes.

* Depth micrometer, measures depths of slots and steps.

* Bore micrometer, typically a three-anvil head on a micrometer base used to accurately measure inside diameters.

* Tube micrometer, used to measure the thickness of tubes.


Specialized types


Each type of micrometer caliper can be fitted with specialized anvils and spindle tips for particular measuring tasks. For example, the anvil may be shaped in the form of a segment of screw thread; in the form of a v-block; in the form of a large disc; etc.

Universal micrometer sets come with interchangeable anvils: flat, spherical, spline, disk, blade, point, knife-edge, etc. The term universal micrometer may also refer to a type of micrometer whose frame has modular components, allowing one micrometer to function as outside mic, depth mic, step mic, etc (often known by the brand names Mul-T-Anvil and Uni-Mike).

Blade mics have a matching set of narrow tips (blades). They allow, for example, the measuring of a narrow o-ring groove.

Pitch-diameter mics have a matching set of thread-shaped tips for measuring the pitch diameter of screw threads.

Limit mics have two anvils and two spindles, and are used like a snap gauge. The part being checked must pass through the first gap and must stop at the second gap in order to be within specification.

Micrometer stops are essentially inside mics that are mounted on the table of a manual milling machine or other machine tool, in place of simple stops. They help the operator to position the table precisely.
source :http://en.wikipedia.org/wiki/Micrometer#Types

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Micrometer : Reading

Inch system

Micrometer thimble showing 0.276 inch
The spindle of an inch-system micrometer has 40 threads per inch, so that one turn moves the spindle axially 0.025 inch (1 ÷ 40 = 0.025), equal to the distance between two graduations on the frame. The 25 graduations on the thimble allow the 0.025 inch to be further divided, so that turning the thimble through one division moves the spindle axially 0.001 inch (0.025 ÷ 25 = 0.001). Thus, the reading is given by the number of whole divisions that are visible on the scale of the frame, multiplied by 25 (the number of thousandths of an inch that each division represents), plus the number of that division on the thimble which coincides with the axial zero line on the frame. The result will be the diameter expressed in thousandths of an inch. As the numbers 1, 2, 3, etc., appear below every fourth sub-division on the frame, indicating hundreds of thousandths, the reading can easily be taken mentally.

Suppose the thimble were screwed out so that graduation 2, and three additional sub-divisions, were visible (as shown in the image), and that graduation 1 on the thimble coincided with the axial line on the frame. The reading then would be 0.2000 + 0.075 + 0.001, or .276 inch.


Metric system

Micrometer thimble reading 5.78mm
The spindle of an ordinary metric micrometer has 2 threads per millimetre, and thus one complete revolution moves the spindle through a distance of 0.5 millimetre. The longitudinal line on the frame is graduated with 1 millimetre divisions and 0.5 millimetre subdivisions. The thimble has 50 graduations, each being 0.01 millimetre (one-hundredth of a millimetre). Thus, the reading is given by the number of millimetre divisions visible on the scale of the sleeve plus the particular division on the thimble which coincides with the axial line on the sleeve.

Suppose that the thimble were screwed out so that graduation 5, and one additional 0.5 subdivision were visible (as shown in the image), and that graduation 28 on the thimble coincided with the axial line on the sleeve. The reading then would be 5.00 + 0.5 + 0.28 = 5.78 mm.


Vernier


Micrometer sleeve (with vernier) reading 5.783mm
Some micrometers are provided with a vernier scale on the sleeve in addition to the regular graduations. These permit measurements within 0.001 millimetre to be made on metric micrometers, or 0.0001 inches on inch-system micrometers.

The additional digit of these micrometers is obtained by finding the line on the sleeve vernier scale which exactly coincides with one on the thimble. The number of this coinciding vernier line represents the additional digit.

Thus, the reading for metric micrometers of this type is the number of whole millimetres (if any) and the number of hundredths of a millimetre, as with an ordinary micrometer, and the number of thousandths of a millimetre given by the coinciding vernier line on the sleeve vernier scale.

For example, a measurement of 5.783 millimetres would be obtained by reading 5.5 millimetres on the sleeve, and then adding 0.28 millimetre as determined by the thimble. The vernier would then be used to read the 0.003 (as shown in the image).

Inch micrometers are read in a similar fashion.

Note: 0.01 millimetre = 0.000393 inch, and 0.002 millimetre = 0.000078 inch (78 millionths) or alternately, 0.0001 inch = 0.00254 millimetres. Therefore, metric micrometers provide smaller measuring increments than comparable inch unit micrometers—the smallest graduation of an ordinary inch reading micrometer is 0.001 inch; the vernier type has graduations down to 0.0001 inch (0.00254 mm). When using either a metric or inch micrometer, without a vernier, smaller readings than those graduated may of course be obtained by visual interpolation between graduations.

source :http://en.wikipedia.org/wiki/Micrometer#Reading

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Micrometer : Parts



A micrometer is composed of:

Frame
The C-shaped body that holds the anvil and barrel in constant relation to each other. It is thick because it needs to minimize flexion, expansion, and contraction, which would distort the measurement.
The frame is heavy and consequently has a high thermal mass, to prevent substantial heating up by the holding hand/fingers.
Explanation: if you hold the frame long enough so that it heats up by 10°C, then the increase in length of any 10 cm linear piece of steel is of magnitude 1/100 mm. For micrometers this is their typical accuracy range.
Micrometers typically have a temperature specified, at which the measurement is correct.

Anvil
The shiny part that the spindle moves toward, and that the sample rests against.

Sleeve / barrel / stock
The stationary round part with the linear scale on it. Sometimes vernier markings.

Lock nut / lock-ring / thimble lock
The knurled part (or lever) that one can tighten to hold the spindle stationary, such as when momentarily holding a measurement.

Screw
(not seen) The heart of the micrometer, as explained under "Operating principles". It is inside the barrel. (No wonder that the usual name for the device in German is Messschraube, literally "measuring screw".)

Spindle
The shiny cylindrical part that the thimble causes to move toward the anvil.

Thimble
The part that one's thumb turns. Graduated markings.

Ratchet stop
(not shown in illustration) Device on end of handle that limits applied pressure by slipping at a calibrated torque.
source : http://en.wikipedia.org/wiki/Micrometer#Parts

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Micrometer : History of the device and its name


The word micrometer is a neoclassical coinage from Greek micros, "small", and metron, "measure". Merriam-Webster Collegiate[2] says that English got it from French and that its first known appearance in English writing was in 1670. Neither the metre nor the micrometre nor the micrometer (device) as we know them today existed at that time. However, humans of that time did have much need for, and interest in, the ability to measure small things, and small differences; the word no doubt was coined in reference to this endeavor, even if it did not refer specifically to its present-day senses.

The first ever micrometric screw was invented by William Gascoigne in the 17th century, as an enhancement of the vernier; it was used in a telescope to measure angular distances between stars. Its adaptation for the precise measurement of handheld objects was made by Jean Laurent Palmer of Paris in 1848[3]; the device is therefore often called palmer in French, and tornillo de Palmer ("Palmer screw") in Spanish. (Those languages also use the micrometer cognates: micromètre, micrómetro.) The micrometer caliper was introduced to the mass market in anglophone countries by Brown & Sharpe in 1867,[4] allowing the penetration of the instrument's use into the average machine shop. Brown & Sharpe were inspired by several earlier devices, one of them being Palmer's design. In 1888 Edward Williams Morley added to the precision of micrometric measurements and proved their accuracy in a complex series of experiments.
source :http://en.wikipedia.org/wiki/Micrometer#Torque_repeatability_via_torque-limiting_ratchets_or_sleeves

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Reading a Vernier

A Vernier allows a precise reading of some value. In the figure to the right, the Vernier moves up and down to measure a position on the Scale. This could be part of a barometer which reads atmospheric pressure.

The "pointer" is the line on the vernier labelled "0". Thus the measured position is almost exactly 756 in whatever units the scale is calibrated in.

If you look closely you will see that the distance between the divisions on the vernier are not the same as the divisions on the scale. The 0 line on the vernier lines up at 756 on the scale, but the 10 line on the vernier lines up at 765 on the scale. Thus the distance between the divisions on the vernier are 90% of the distance between the divisions on the scale.



If we do another reading with the vernier at a different position, the pointer, the line marked 0, may not line up exactly with one of the lines on the scale. Here the "pointer" lines up at approximately 756.5 on the scale.

If you look you will see that only one line on the vernier lines up exactly with one of the lines on the scale, the 5 line. This means that our first guess was correct: the reading is 756.5.

Here is a final example, with the vernier at yet another position. The pointer points to a value that is obviously greater than 756.5 and also less than 757.0. Looking for divisions on the vernier that match a division on the scale, the 7 line matches fairly closely. So the reading is about 756.7.


In fact, the 7 line on the vernier appears to be a little bit above the corresponding line on the scale. The 8 line on the vernier is clearly somewhat below the corresponding line of the scale. So with sharp eyes one might report this reading as 756.73 ± 0.02.

This "reading error" of ± 0.02 is probably the correct error of precision to specify for all measurements done with this apparatus.


Now we shall use a simulation of a Vernier Caliper. A caliper measures a length, and in the following figure we show a caliper being used to measure the length of an Object. The Object will be placed between the "jaws" of the caliper. The Object is almost exactly 75 mm (2.95 in) long.
source :http://www.upscale.utoronto.ca/PVB/Harrison/Vernier/Vernier.html

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Vernier Caliper


Instructions on use

* The Vernier caliper is an extremely precise measuring instrument; the reading error is 1/20 mm = 0.05 mm.

* Close the jaws lightly on the object to be measured.

* If you are measuring something with a round cross section, make sure that the axis of the object is perpendicular to the caliper. This is necessary to ensure that you are measuring the full diameter and not merely a chord.

* Ignore the top scale, which is calibrated in inches.

* Use the bottom scale, which is in metric units.

* Notice that there is a fixed scale and a sliding scale.

* The boldface numbers on the fixed scale are centimeters.

* The tick marks on the fixed scale between the boldface numbers are millimeters.

* There are ten tick marks on the sliding scale. The left-most tick mark on the sliding scale will let you read from the fixed scale the number of whole millimeters that the jaws are opened.



* In the example above, the leftmost tick mark on the sliding scale is between 21 mm and 22 mm, so the number of whole millimeters is 21.

* Next we find the tenths of millimeters. Notice that the ten tick marks on the sliding scale are the same width as nine ticks marks on the fixed scale. This means that at most one of the tick marks on the sliding scale will align with a tick mark on the fixed scale; the others will miss.

* The number of the aligned tick mark on the sliding scale tells you the number of tenths of millimeters. In the example above, the 3rd tick mark on the sliding scale is in coincidence with the one above it, so the caliper reading is (21.30 ± 0.05) mm.

* If two adjacent tick marks on the sliding scale look equally aligned with their
counterparts on the fixed scale, then the reading is half way between the two marks. In the example above, if the 3rd and 4th tick marks on the sliding scale looked to be equally aligned, then the reading would be (21.35 ± 0.05) mm.

* On those rare occasions when the reading just happens to be a "nice" number like 2 cm, don't forget to include the zero decimal places showing the precision of the measurement and the reading error. So not 2 cm, but rather (2.000 ± 0.005) cm or (20.00 ± 0.05) mm.
source : http://www.physics.smu.edu/~scalise/apparatus/caliper/

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My Articles

I have summarized the various articles and information available. Then my concert from one page to another page, so it formed a series of articles and information that is quite long.
The following article was collated. hopefully useful...
a. Carburizing
b. Maintenance
c. Surface Treatment
d. Welding

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Gallery

Sorry, This page is still in the process of development.
Thank you very much for visiting us.

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Ungkapan kata cinta ku..

KATA - KATA KU TENTANG SEMUA........

“..Engkau takkan dapat menatap matahari, karena matamu tidak lebih besar daripadanya. Engkau takkan dapat menahan sinarnya, karena tatapan matamu tidak lebih tajam dari cercahnya. Tapi satuhal yang kutahu : Sekalipun kau memalingkan wajahmu darinya, ia tetap menatapmu, memberi kehangatan dihatimu, dan kecerahan dalam segala harimu…”

“..Sebelum kamu tidur biarlah bibirmu tersenyum manis, pejamkanlah matamu dan lepaskan segala bebanmu. Biarlah tubuhmu terbaring tenang. Segala yang terjadi sepanjang hari tadi biarlah berlalu. Janganlah kiranya air matamu mengalir karena kegagalan, tapi jadikanlah semuanya itu pelajaran. Tataplah kedepan dan lihatlah, : Segala yang baik akan menyertaimu…”


“..Seandainya engkau punya seribu permohonan dalam doamu saat ini - biarlah kiranya
satu dari seribu permohonan itu adalah untukku…”


“..Tidurlah dengan tenang seperti seorang anak dipangkuan ibunya. Air matamu akan kuhapus dengan tanganku, lukamu akan kubalut dengan rambutku. Tidurlah dengan tenang_sbab aku menjagamu, keselamatanmu adalah pertaruhan hidupku- tanganku menopangmu. Tidurlah dengan tenang_sbab jubahku menyelimutimu, dinginnya malam takkan mengusikmu. Tidurlah dengan tenang_sbab nyanyianku menghiburmu- doaku menyertaimu. Tidurlah dengan tenang_sbab letihmu tlah kuambil darimu, dan damai sejahtra penuh atasmu…”


“..Sebelum kamu tidur biarlah sedikit waktumu mengenangku, nyanyikan senandung pengobat rindu – kelembutanmu mendamaikanku…”

“..Banyak hal yang membuatku kecewa dan bersedih. Tapi satu hal yang kutahu, : Bahwa kau tersenyum untukku hari ini, dan membuatku melupakan semuanya itu…”


“..Kita pikir kita akan mampu - membangunkan matahari sebelum ia terbit. Padahal matahari sudah terbit sebelum kita menantikannya. Oleh karena cercah cahayanyalah kita terjaga- dan mengakhiri tidur kita, untuk memulai hari_dengan penuh sukacita , dan senyuman dan dengan segudang harapan…”


“..Kita sulit melupakan seseorang, karena dia menyentuh kita, dan ‘sentuhannya’ tepat di hati kita…”


“..Biarlah setiap perkataan kita membangun - buah pikiran kita adalah inspirasi - senyuman kita meredakan amarah - tatapan mata kita adalah semangat yang menyala - derap langkah kita adalah peneguhan bagi yang lemah - tangan kita adalah penopang - nyanyian kita adalah penghiburan,.’.Dan segala yang kita miliki adalah bagi orang lain, tapi bukan karena orang lain kita berbuat demikian - tapi karena itulah kita, cerminan dari segala yang ada dalam hati kita…”


“..Kita mencari sesuatu_tapi kita kecewa, karena apa yang kita cari tidak kita temukan. Padahal apa yang kita cari sebenarnya tidak ada, atau mungkin apa yang kita cari bukanlah milik kita…”


“..Embun pagi menyapamu - tapi kau diam saja. Matahari menatapmu - tapi kau
memalingkan wajahmu. Ayam berkokok memanggilmu - tapi kau mengacuhkannya.. Tapi kali ini akan yang datang, membawa segenggam air ditanganku - membasuh wajahmu, hingga kau terjaga dari tidurmu dan menyadari bahwa semua telah menantimu…”



“..Kita merasa sendiri - padahal kita berada dalam keramaian. Kita merasa terpenjara- padahal kita berada dalam kebebasan. Kita merasa gagal- padahal kita berada dalam kesuksesan. Kita merasa dalam keterpurukan- padahal kita berada dalam kejayaan… Tapi kita adalah orang-orang yang menang, karena kita dapat melangkah dalam dua hal yang berbeda sekaligus- namun kita masih dapat bertahan…”


“..Andai bumi dapat kugenggam - akan kuberikan kepadamu. Andai bintang dapat kugapai- akan kuserahkan kepadamu. Andai matahari dalam naunganku- itupun akan kupersembahkan kepadamu…Tapi segala yang besar- segala yang megah- dan segala yang berharga tidak ada padaku. Setitik kasih yang ada ditelapak tanganku itulah yang kupunya. Semua yang ada padaku akan kutaruh dikakimu, sebagai dasar tempatmu berpijak, dan sebagai dasar bahwa aku mengasihimu…”


“..Tadi seorang pengemis minta sesuatu kepadaku. Aku menatapnya dan berkata, :
“ Maaf, aku tidak punya sesuatu yang berharga untukmu, tapi yang kupunya hanyalah sebuah karung”? …Lalu pengemis itu bertanya, ; “ Mengapa kamu memberi karung padaku “? Aku berkata padanya, : “.. Aku punya seorang sahabat namanya……., Ia punya segudang kasih dihatinya. Nanti karungmu akan terisi penuh oleh senyumannya, dan kamu tak perlu mengemis lagi…”


“..Mungkin butuh sejuta kata untuk menafsirkan ‘ Cinta ‘, bahkan itupun tidak cukup. Karena cinta tidak dibentuk oleh sekumpulan kata-kata. Ia dapat berdiri tegak dalam kelemahan, berjalan dalam kebuntuan, dan berbicara dalam kebisuan…”



“..Satu kata yang indah tidaklah cukup untuk mewakili sebuah perasaan cinta. Karena cinta lebih dari sebuah kata, bahkan seribu kata indah sekalipun tidak dapat menyamainya. Tapi satu kata yang indah bisa jadi adalah sebuah cinta, karena ada rasa dalam kata itu - dan itulah yang membuat kata itu menjadi hidup…”


“..Saat terindah bersamamu - adalah ketika aku melihat dengan jelas matamu. Karena ketika aku menatapmu, aku melihat bayanganku ada dimatamu. Bahkan ketika kau menangis sekalipun - bayangan itu terlihat lebih jelas. Sekiranya engkau berkenan- ijinkan aku menghapus air itu dari matamu, agar bukan sekedar bayanganku saja yang ada didalam matamu, tapi aku sendiri secara nyata dihatimu…”


“..Kiranya hari ini kau tersenyum, bersukacita, dan penuh dengan damai sejahtra. Dan sekiranya orang-orang yang melihatmu, mereka akan berkata, : “ Sungguh hatiku bersuka karenanya…”


“..Bangun dan beranjaklah dari tempat tidurmu, keluar dan lihatlah - matahari telah tiba, ia menyapa kepada seluruh dunia, dan kepadamu juga…”


“..Perasaan hanya berbicara tentang hal-hal yang indah dan menyenangkan saja, tapi hati nurani berbicara tentang kejujuran dan kebaikan. mereka sering berjalan beriringan, namun kadang mereka berlawanan…”


“..Berikan aku satu saja dari sejuta senyuman yang kau miliki, maka aku akan berperang melawan kemarahanku, dan akulah pemenangnya…”


“..Basuhlah wajahmu dengan segenggam air yang kuberikan, lalu perhatikan apa yang terjadi…”

“..Engkau tidur dalam ketenangan - karena tubuhmu terbaring beralaskan kedamaian. Bibirmu tersenyum manis - karena hatimu berselimutkan kasih sayang, dan ketika engkau terjaga dari tidurmu - segala yang baik pun akan menantimu…”


“..Aku hendak memberi sekuntum mawar untukmu - tapi seketika aku mengurunkan niatku. Karena aku pikir ia akan layu dalam beberapa waktu, dan kau akan membuangnya. Namun biarlah ‘perkataan manis nan indah’ yang kupersembahkan, dan sekiranya kau mendengarnya – ia akan melekat dihatimu…”


“..Dan seperti matahari yang tidak pernah lupa untuk terbit dan terbenam, - dan seperti gelombang laut yang tak pernah berhenti, demikianlah aku mengenangmu dalam segala hariku…”

“..Indahnya sinar mentari diwaktu pagi – tidaklah dapat menyamai keindahan senyumanmu. Karena sinar hanya menyentuh bagian permukaan saja, tapi senyumanmu menyentuh hingga kedalam relung hati…”

“..Sekiranya engkau berkenan – ijinkanlah aku memetik sekuntum mawar dari taman hatimu, dan biarlah keindahanmu bersamaku dalam sepanjang hariku…”


“..Bintang malam bertabur dengan indahnya – cercahnya menghalau gelapnya malam – sinarnya menerangi jalan, hingga tak satupun sesuatu luput dari pandangan. Namun ada satu Bintang yang sungguh menggetarkan, cahayanya meneduhkan, dan terangnya mendamaikan…”


“..Engkau seperti pelangi dalam terang – awan mengiringmu dengan setia. Cahayamu memberi kehidupan bagi jiwa yang binasa - menuntun hati yang terhilang. Sinarmu meneduhkan bagai rembulan – menghapus air mata menjadi senyuman.
Kau…teruslah disini – masuklah kedalam jiwaku, dengarlah ratapku, berdiamlah dalam rasaku…”

“..Ingin rasanya aku membelaimu – dalam keheningan malam nan syahdu, merajut mimpi dalam kepastian. Ingin kucurahkan segala rasa – dalam senyum tak berkesudah, menenun harap dalam jiwa. Kan kuukir namamu dalam namaku – kusentuh ia dengan cinta sejati, kugenggam ia dalam sanubari …”
“..Rasanya sudah seribu tahun aku mengenalmu, - karena aku merasa dekat darimu. Engkau memberi jawaban lebih dari yang kupikirkan. Ketika aku terbata - bata dalam berucap - engkau menuntun lidahku, menghapus keluh dari jiwaku. Engkau berkenan mengajarkanku - sebuah bahasa lain yang belum aku ketahui, hingga aku mengerti segala perkataanmu. Sedemikian murninya hatimu - hingga aku sungguh mengagumimu, untuk mengerti segala hal tentang dirimu…”


“..Cinta sering membuat kita menangis.., namun oleh karena tangisan itu kita jadi bisa menghargainya…”

“..Aku berdiri didepan pintu rumahmu dan mengetuk. Sekiranya engkau berkenan – bukalah pintumu bagiku, bawa aku masuk dan menikmati indahnya rumah hatimu…”

“..Kekayaanmu membuatku ingin mencuri sesuatu milikmu. Kemurahanmu membuatku ingin meng-hargai sesuatu darimu. Keindahanmu membuatku ingin berdiam didekatmu. Kebaikanmu membuatku berbelas dihadapanmu.. Dan semua yang engkau miliki sungguh mempesonaku, karena semua bersumber didalam hati…”

“..Hingga saat ini tetap saja aku tidak mengerti, ombak membawa pergi nama yang ku tulis dihamparan pasir itu. Batinku bertanya, : mengapa dia membawanya dan kapan dia akan kembali..? Tapi dia hanya diam, karena memang dia tidak dapat berbicara…
Ombak datang dan pergi tanpa tahu untuk apa dia melakukan itu, tapi Cinta juga datang dan pergi – namun ia mengerti mengapa ia berbuat demikian…”



“..Sekalipun seluruh dunia membecimu – aku akan mengasihimu, sekalipun seluruh dunia menghakimimu – aku akan membelamu, sekalipun seluruh dunia hendak memenjarakanmu – aku akan membebaskanmu, dan sekalipun seluruh dunia berhasrat membunuhmu – aku akan menyelamatkanmu..
‘Dan sekiranya seluruh dunia melakukan seperti apa yang kuperbuat bagimu, ‘siapakah aku dihatimu…”

“..Tak terlukiskan betapa indahnya hatimu – hingga seribu puisi pun enggan bersanding denganmu…”

“..Tak terbersit sedikit pun untuk menyakitimu – sebab kau terlalu lembut untuk disakiti, sebab tak mungkin aku menyakitimu – karena kau adalah bagian dalam diriku…”

“..Sedemikian halnya banyak pertanyaan yang kita terima sepanjang hari, seperti langkah – langkah yang kita lalui sepanjang waktu. Dan ketika kita telah tiba disuatu tempat yang kita harapkan – itulah jawaban dari semua pertanyaan itu…”

“..Sedetik bersamamu adalah pengalaman yang berharga bagiku, dan setiap detik takkan ada lagi yang tersiakan oleh karenamu…”

“..Bermusuhan denganmu mungkin saja lebih baik – daripada bersahabat dengan kebimbangan, berperang denganmu mungkin saja lebih bermakna – daripada berbicara dengan ketidakmampuan, dan binasa ditanganmu mungkin saja lebih terhormat – daripada kembali dalam kekalahan…”

“..Biarlah garda dan prisaiku menjagamu malam ini, tidurmu akan tenang – sebab tanganku menaungimu, nyanyianku memanjakanmu – sebab kelembutan hati adalah senandungmu..
Tak terhingga betapa akan bahagianya engkau – sebab mimpi indah menerbangkanmu dengan sayapnya, dan seluruh keindahan bersamamu dalam setia…”

“..Berapa ratus mil yang telah engkau lalui – atau berapa ribu mil yang telah engkau jalani, namun kakimu tak pernah letih, dan tubuhmu tak pernah mengeluh karenanya..’Sbab sesuatu yang engkau cari lebih berharga daripada semua pengorbananmu, dan setiap pengorbananmu adalah langkah awal dari kemenanganmu…”

“..Tak tergantikan betapa indahnya sang mentari itu – sinarnya takkan lekang oleh waktu.. sekarang ia telah tiba – menyapamu dengan lembut, menghangatkan jiwamu, dan menuntunmu sepanjang waktumu…”


“..Dalam gelap ia masih mampu bersinar – dalam dingin ia masih mampu menghangatkan, dalam sepi ia masih mampu berbicara..’Dan itulah Cinta – sanggup meruntuhkan hal yang tidak mungkin menjadi nyata, dan kali ini ia telah datang, memenuhi hatimu dalam sepanjang waktumu…”

“..Satu senyumanmu bisa memberi arti bagi orang yang menerimanya – sekiranya setiap hari engkau memberi satu senyum untuk seribu orang.. ‘dan apakah yang akan terjadi jika engkau melakukan itu disepanjang hidupmu…”

“..’Dan setiap hari adalah bahagia – karena hati adalah dasar dari semuanya..’Ia akan membalut lukamu – menyeka air matamu, dan memulihkan jiwamu…”

“..Satu hal – dua hal – ataupun mungkin segala sesuatu dapat berubah dalam waktu yang cepat – diluar dari apa yang kita pikirkan..’ Kita mencari sesuatu seakan-akan ada hal yang hilang dalam diri kita, padahal dengan seiring waktu yang berjalan kita telah menemukan banyak hal, dan itulah yang menuntun segala perjalanan kita…”

“.. Mengukir hari dalam hati seperti halnya aku memandangmu indah adanya…”

“..’Dan bintang – bintang akan menari serta bernyanyi untukmu, mereka hendak menyenangkan hatimu, menghapus letihmu, dan menemani malammu dalam damai…”

“..Kakimu telah jauh melangkah – namun perjalananmu belumlah usai, sebab apa yang engkau cari belum jadi milikmu, tapi ia sudah berada dihadapanmu - berdiri dalam kesempurnaannya…”

“..Takkan kubiarkan air matamu mengalir tersia – ‘kan ku seka ia dengan tanganku, dalam bejana jiwa ku taruh ia dengan lembut, dan oleh perantaraan waktu ia akan abadi didalam hati…”

“..Seperti sekuntum bunga ini yang takkan pernah layu oleh waktu - demikianlah aku memandangmu sempurna sepanjang masaku…”

“..Dan segala sesuatu mungkin saja terjadi – tapi janganlah kiranya damai itu pergi dari hatimu, sbab disanalah benteng pertahananku - tempatku berteduh…”

“..Tanpa kusadari aku telah bangkit dari tidurku – namun tetap saja aku masih merasa bermimpi, sbab sebuah nyanyian baru sungguh mendamaikanku – membisikkkanku seribu bahasa lain yang belum aku mengerti, dan dalam sejuta kebimbangan aku telah diteguhkan…”

“..Hapuslah air matamu dan gantikanlah dengan senyuman – lepaskanlah bebanmu maka bebaslah hatimu, sbab mata adalah pelita tubuh – dan hati adalah pelita jiwa..’Langkahmu akan lurus – kakimu takkan tersandung, dan janganlah kiranya hatimu menjadi bimbang – sbab cinta tlah melekat dihatimu…”

“..Sekiranya damai dan kemurahan hati penuh atasmu – berkenanlah untuk berbagi padaku, biar apa yang ada dihatimu – ada juga didalam hatiku…”

“..Sembuhlah lukamu dan nyanyikanlah senandung penuh Cinta, takkan pernah letih ia mengiringmu – tiap langkahmu dituntunnya, tanganmu dipegangnya erat..’ Sekalipun dalam tempat yang gelap ia takkan meninggalkanmu – hingga kau tiba ditempat dimana hatimu berpaut, sejak hari ini dan selamanya - ia akan bersamamu…”

“..Seperti salju yang terus membeku – demikianlah kau mengenangnya selalu, ‘Engkau memelihara keluh dihatimu – padahal sesuatu yang indah tlah menantimu. Ia hendak masuk kedalam hatimu, mengubah keluh menjadi sukacita – menghapus air mata menjadi senyuman, ia akan berdiam dihatimu – dalam segala hal, - dan dalam segala rasamu…”

“..Akankah nafas berhenti – dan masa berakhir, takkan ada lagi waktu ‘tuk berkata. Semua berlalu dan pergi begitu saja - jejak langkah terhilang, airmata mengering, Semua binasa dalam kesiaan, seribu puisi tak lagi berarti – sbab tak ada lagi senyuman, tiap kata menjadi hambar – sbab kau tak menyapa…”



“..Hatiku takut dan gentar – sbab aku ini sendiri dan terluka. Sekiranya aku diberi sayap seperti merpati, aku akan terbang dan mencari tempat yang tenang – biar aku dapat membalut lukaku dan mengejarmu.. - Janganlah bersembunyi dariku, sbab aku menantimu, - sbab hatimu adalah pelita bagi jiwaku...”

“..Seperti tanah kering yang merindukan hujan – demikianlah hati membutuhkan kasih. Tiap rintikan yang jatuh takkan mungkin kembali ke langit – seperti kasih yang takkan pernah kembali sia-sia, - sbab ia telah bersemi dihati yang tulus…”

“..Terkadang kita merasa jauh – padahal kita saling menatap dan menyapa. Betapa besar dan kuatnya tembok yang memisahkan – hingga saat ini tetap saja ia masih berdiri tegak. Sbab tangan tak mampu lagi menopang – dan kaki tlah letih melangkah..’Tapi percayalah ia akan runtuh tepat pada waktunya, bukanlah dengan tangan dan kaki yang melakukannya, melainkan dengan ‘perkataan hati yang tulus’ – maka ia akan runtuh..”

“..Aku hendak menawarkan sesuatu kepadamu – sebuah harapan baru yang belum pernah engkau ketahui – yang akan mengantarkanmu ketempat yang belum engkau lalui..
‘ Ikutlah dan berjalanlah bersamaku – sebab tanganmu kupegang erat, engkau akan melihat ribuan bintang menari untukmu, - dan sinarnya bernyanyi bagi hatimu…”

“..Sebab banyak orang yang berhasrat membunuhku – namun biarkanku bersembunyi dalam bayangmu, sebab kutahu ada damai disitu – jiwaku pun menjadi tenang, - sebab hatimu adalah prisai bagi jiwaku...”

“..Sungguh betapa bahagianya aku ketika kau tersenyum buatku – sebab senyummu memberi arti bagiku, - dan itulah yang menantikanku…”

“..Tidurlah lembayu senja – tidurlah dalam keharibaan kasih, seribu puisi terlantun manis ditelingamu – mengantarkanmu ketempat damai itu, tak ada lagi air mata – sedih pun enggan mendekat padamu – sbab hati penuh belaian kasih..
Dinginnya malam takkan menusuk tulangmu - sbab kasih dan damai sejahtra telah penuh atasmu, sejak saat ini ia akan berdiam dalam jiwamu -, ditempat perhentian hatimu…”

“..Sekali ini saja dengarkanlah aku, - tidakkah kau mengerti bahwa tubuh memerlukan pakaian dan hati membutuhkan kasih..
Berapa lama lagi kau akan berdiam – tidakkah kau melihat ada bayangan dihadapanmu, menari dan bernyanyi ia bagi jiwamu, penuhkan hasratmu dalam keabadian..
Dimanakah sejatimu itu – aku telah menemukanmu dalam mimpiku tetapi kau selalu saja bersembunyi – dalam gelap kau seakan menghilang, namun tetap saja terang itu mengejarmu dengan setia…”

“..Ditelapak tanganku telah tertulis namamu – seperti sebuah cincin yang selalu melekat dijari, dalam tanganku kan ku jagai kau terus – seperti air sungai yang terus mengalir, - dalam genggamanku keselamatanmu adalah pertaruhan hidupku…”

“..Sedapat mungkin jika hal itu berkenan kepadamu – maafkanlah aku.., biarlah perdamaian yang darimu ada padaku – sebab ku tahu itu sungguh berarti bagiku…”

“..Setiap kali aku mengingatmu adalah perjalanan panjang bagiku, - sebab kutahu namamu telah terukir indah dihatiku – melekat erat dalam setiap bayangku…”

“..Aku telah bangkit dari pembaringanku dan aku mengingatmu.. Tinggal sedikit lagi waktu maka semua akan berubah – rembulan tak lagi berkuasa - sbab mentari telah menghalaunya, ia akan menghanguskanmu seperti jerami dimusim kering..
Berapa lama lagi kau akan bertahan – sebab segala sesuatu akan menjadi nyata…”

“..Tak ada rasa yang tak bernilai – sebab semua berasal dari hati, tangan menopang, perkataan meneguhkan – namun hatilah yang merasakan.. ‘ ia berbicara ketika semua tak mampu lagi berkata, dalam duka dan bahagia ia selalu terdepan – seperti garda dan perisai perang – menghalau musuh tanpa gentar…”

“..Telah tiba saatnya untuk menyudahi hari – dalam tenang aku hendak membaringkan tubuh – hingga kedua mata terpejam penuh, - ‘ namun haruskah aku melupakanmu dan tidur tanpa mengenangmu.. -‘ seperti rembulan yang selalu hadir dimalam hari – demikian waktu yang berlalu akan penuh arti…”

“..Tanpamu aku lemah – sebab tanganku kau pegang erat, mengisi hari dalam suka dan sedihku, - dengan segenap hati aku mengasihimu…”

“..sebuah kebanggaan bagiku bisa mengenalmu – seperti matahari yang selalu menghangatkan, - demikianlah setiap orang yang memandangmu akan bersuka…”

“..Dengan sepenuh hati aku hendak mengenangmu – sebab setiap kali aku mengingatmu engkau menambahkan semangat bagiku, dalam keruntuhan hati aku hendak menghampirimu – menyapamu sebelum matahari menghardikku.. Dengan segenap nafas aku hendak melantunkan sebait bagimu – nyanyian baru dari hati yang merindu…”

“..Lebih dari nafas aku membutuhkanmu – sebab rasamu telah membangkitkanku dalam keruntuhan jiwa, lebih dari nafas kau membentuk hariku, - dalam seribu asa kau ubah hatiku – hingga tiap detik adalah harapan baru..- ’Seperti goresan kecil ditanganku, begitulah aku memandangmu – terukir indah tanpa pudar…”

“..mestinya kau telah disini – sebab aku telah menantimu dimasa perihku, telah kudirikan istana bagi jiwamu, kuukir lembut namamu dalam tiap sudutnya.. – ‘ sudilah sejenak saja kemari – memandang istana yang telah kubangun untukmu, dengan airmata telah ku lukis indah wajahmu - biar semua tahu bahwa engkaulah pemiliknya, - dan berkenanlah tinggal disini untuk selamanya, - nikmati harimu dalam segala keinginan hatimu…”

“..Sebab yang kumau adalah kau menjaga hatiku – aku mengenalmu seperti butiran mutiara didasar laut, dalam kegelapan kau selalu bersinar terang - sebab lebih dari semua itu tak ada pelita yang kutemui, - hingga saat ini hatimu adalah pelita tak tergantikan…”

“..Disaat kau tersandung dan kakimu terluka janganlah pernah menangis – mungkin itulah waktu terbaik bagimu untuk berhenti dan berteduh sejenak, sebab engkau telah memaksa diri untuk terus melangkah sementara kakimu belum sepenuhnya pulih..- biarkan hatimu tertegun sejenak – menatap segala sesuatu yang telah engkau raih, dan nikmatilah semuanya itu sebagai sebuah hadiah dari setiap pengorbananmu, - dan tinggal sedikit lagi waktu maka semua akan jadi milikmu…”


“..Telah kusadari segala sesuatu bisa terjadi – meskipun aku sendiri aku akan terus melangkah, sebab perjalananku ialah seperti sebuah peperangan – yang ada hanyalah maju dan mundur – tak ada kata menyerah dan berdiam, sebab pertaruhanku bukan hanya hidupku, tapi juga orang-orang yang ada dihati…”

“..aku hendak menentramkan jiwaku sebelum aku membaringkan tubuh – sebab tak ada yang lebih indah lebih dari hati yang tenang, dalam damai ada senyum – seribu nyanyian meruntuhkan duka..
‘ aku menjagamu hingga kedalaman hatimu – lebih dari hidup yang kumiliki adalah sebuah perebutan bagi kemenanganmu…”

“..Sementara aku menantikan fajar – biarlah hatiku penuh mengingatmu, seperti matahari yang terbit menghiasi pagi – demikianlah namamu adalah perhiasan jiwaku…”

“..Sebab perjalananku bukanlah tanpa arah – begitu besar harapan yang telah terukir dalam hati, tertulis lembut dilembar jiwa – biar tak terpudarkan oleh masa dan waktu, - sebab hati adalah lembaran jiwa dan airmata-lah yang menorehkannya – hingga tiap detik adalah harapan baru yang indah, - dan semua yang tertoreh dalam lembaran itu berasal dari kepenuhan hatiku…”


Mengkhayal berarti sesuatu yang indah. sebab indah pastilah berkhayal dengan apa yang akan aku lalui dan dengan siapa akan nantinya berakhir… mengeluh dengan banyak peluh tertatih dengan syarat isyarat dunia yang meluas…. Nan berkembang bak kembang tak akan selesai sampai aku memetiknya……’’

Akulah anak manusia dengan jemari jemari alam
Lukisan pun tidak akan tau siapa aku ,karena terdiam terpajang
Tapi lihatlah dengan kasat,jangan sampai bergemuruh runtuh
Andai aku gunung tiada aku luruh,andai aku lukisan tiada aku memudar.

Dan setiap langkah adalah indah,dan beribu jejak adalah hiasan hidup yang akan membuat ku tenang,hening dalam bening, yang ketika menyapaku sambutlah wahai dunia ,kejarlah jangan engkau melangkah misteri ini tidak akan mati…….

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Jumat, 09 Januari 2009

Selecting a Welder for the Farm or Ranch

Selecting a Welder for the Farm or Ranch The weather finally clears, and Wisconsin dairy farmer Al Hoffmann has 385 acres of haylage to cut and store when the chopper blower band for the silo snaps in half. Part of the 3/16 in. steel band has worn paper thin and snapped, and on this Saturday, the nearest replacement band is two days away.


Using a 200 amp Millermatic wire welder, Al saves the band by tack welding it together and then welding on a back up strip of steel. The repaired chopper blower moves more than 800 tons of haylage in the next few days...

...It's evening milking time. Al is half done with his 185 cows when a hinge breaks on the air gate in the milking parlor. Al resumes milking a few minutes later, after he repairs the gate with a portable Millermatic wire welder that runs on 115V household current.

Does every farm or ranch need two or three different types of welders? While Al wouldn't trade in any of his machines, he "can't imagine not having a wire welder. It's easy to use, makes heavy welds, yet still allows me to work on thin sheet metal. I wouldn't have even attempted to repair the chopper blower band with a Stick welder because it was so thin. It would have burned right through."

Because different applications sometimes call for different welding processes, selecting the right welder for your operation is important.

The most common welding processes used for fabricating metals are:

* Stick - Shielded Metal Arc Welding (SMAW)
* MIG - Gas Metal Arc Welding (GMAW, a wire welding process)
* Flux Cored Arc Welding - (FCAW, also a wire welding process)
* TIG - Gas Tungsten Arc Welding (GTAW)
source : http://www.welding.com/articles/bparticle9.htm

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Safety and Scheduled Maintenance Protect Your Welding Assets

Q: What can I do to avoid electrical shocks?

A: Wet working conditions must be avoided, because water is an excellent conductor and electricity will always follow the path of least resistance. Even a person's perspiration can lower the body's resistance to electrical shock. Poor connections and bare spots on cables further increase the possibility of electrical shock, and therefore, daily inspection of these items is recommended. Equipment operators should also routinely inspect for proper ground connections.


Q: How can I inspect and maintain my Miller wire feeder?

A: Periodically inspect the electrode wire drive rolls. If dirty, remove the drive rolls and clean with a wire brush. Deformed drive rolls should be replaced. Drive rolls should be changed, adjusted or cleaned only when the wire feeder is shut off. In addition, check the inlet and outlet guides and replace if they are deformed from wire wear. Remember that when power is applied to a wire feeder, fingers should be kept away from the drive roll area.

Q: What are some important electrode safety considerations?

A: Welding power sources for use with MIG and TIG welding normally are equipped with devices that permit on/off control of the welding power output. If so, the electrode becomes electrically hot when the power source switch is ON and the welding gun switch is closed. Never touch the electrode wire or any conducting object in contact with the electrode circuit, unless the welding power source is off. Welding power sources used for shielded metal arc welding (SMAW or Stick welding) may not be equipped with welding power output on/off control devices. With such equipment, the electrode is electrically hot when the power switch is turned ON.

Q: How should I store my gas cylinders?

A: Cylinders should be securely fastened at all times. Chains are usually used to secure a cylinder to a wall or cylinder cart. When moving or storing a cylinder, a threaded protector cap must be fastened to the top of the cylinder. This protects the valve system should it be bumped or dropped.

Cylinders should not be stored or used in a horizontal position. This is because some cylinders contain a liquid which would leak out or be forced out if the cylinder was laid in a flat position. Also, welding guns and other cables should not be hung on or near cylinders. A gun could cause an arc against the cylinder wall or valve assembly, possibly resulting in a weakened cylinder or even a rupture.

Q: How can I tell if my regulator is faulty?

A: The following symptoms indicate a faulty regulator:

* Leaks - if gas leaks externally.
* Excessive Creep - if delivery pressure continues to rise with the downstream valve closed.
* Faulty Gauge - if gauge pointer does not move off the stop pin when pressurized, nor returns to the stop pin after pressure release. Do not attempt to repair a faulty regulator. It should be sent to your designated Miller repair center, where special techniques and tools are used by trained personnel.


Q: What are some tips for a safe welding environment?

A: The area surrounding the welder will be subjected to light, heat, smoke, sparks and fumes. Permanent booths or portable partitions can be used to contain light rays in one area. The heat and sparks given off are capable of setting flammable materials on fire. Therefore, welding should not be done in areas containing flammable gases, vapors, liquids or dusty locations where explosions are a possibility.

Metals with plating, coatings or paint that come near the region of the arc may give off smoke and fumes during welding. These fumes may pose a health hazard to the lungs, therefore an exhaust hood or booth should be used to remove fumes from the area.

When welding in confined spaces, such as inside tanks, large containers or even compartments of a ship, toxic fumes may gather. Also, in an enclosed room, breathable oxygen can be replaced by shielding gases used for welding or purging. Care must be taken to ensure enough clean air for breathing. In many companies, it is routine to provide welders with air masks or self-contained breathing equipment.

Q: How should an operator dress for optimum safety?

A: Gloves and clothing should be flame-resistant. Clothing made from a dark-colored, tightly woven material is best suited for welding. Gauntlet-type leather gloves should be worn to protect the hands and wrists. Shirt collars and shirt cuffs should be buttoned, and open front pockets are not advisable as they may catch sparks. Also, operators should never store matches or lighters in their pockets. Pants cuffs are not recommended, as they will also catch sparks. Tennis shoes do not qualify as adequate foot protection. High-top leather shoes or boots are absolutely necessary.

Q: Is there a daily maintenance schedule I should follow?

A: Below is a general engine drive routine daily maintenance schedule, but it should be modified according to a company's specific conditions.

By following a regimen of appropriate and thorough maintenance and safety, a welder from Miller Electric can run dependably for decades. Designed to withstand rough use, these machines use high quality components and are tested for durability.

Always refer to Miller Electric's owner's manual for a thorough explanation of safety and maintenance. This article does not give complete coverage of all the maintenance and safety issues in existence.
Maintenance Schedule Chart

8 Hours

* Wipe up oil and fuel spills immediately
* Check fluid levels (oil & fuel)
* Service the air filter (refer to engine manual for specifics)

50 Hours

* Service air filter element (refer to engine manual for specifics)
* ChClean and tighten weld terminals

100 Hours

* Change oil
* Change oil filter (refer to engine manual for specifics)
* Clean and tighten battery connections
* Clean cooling system (refer to engine manual for specifics)

200 Hours

* Replace unreadable labels (order from parts list)
* Replace fuel filter
* Check valve clearance (refer to engine manual for specifics)

250 Hours

* Check and clean spark arrestor

500 Hours

* Tape or replace cracked cables
* Clean/Set injectors (refer to engine manual for specifics)

1000 Hours

* Blow out or vacuum inside equipment. During heavy service, do this monthly.
source : http://www.welding.com/articles/bparticle8.htm

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Examining Pulsed MIG (GMAW-P) Welding

A brief listing of advantages provided by pulsed MIG welding (GMAW-P) usually encourages welding technicians to see if this technology may be appropriate for their application:

* All position welding with spray-like transfer
* Travel speeds increase up to 35% over short circuit transfer
* Ability to fine tune arc wave form
* Significantly reduced spatter compared to short circuit transfer
* Minimizes distortion - compared to spray transfer
* Better bead appearance
* Lower fume emissions, when properly set up


While this process offers many advantages, it's important to evaluate your application carefully before making a move to pulsed MIG. Applications best suited for GMAW-P are those currently using short circuit transfer method for welding 14 gauge (1.8 mm) to 3/8 in. (9.5 mm) steel, either manual or automated. In these situations, GMAW-P notably increases production rates, significantly reduces spatter and improves bead appearance.
The ability to tailor the arc wave form with pulsed spray transfer lets users develop beads with improved width-to-depth ratios. For example, some people use pulsed spray transfer for the fill (and even root) passes on pipe welds because they can create a penetrating arc that produces an x-ray quality weld. Others use pulsed spray transfer for overlay work (such as a nickel or inconel jacket) because they can create a wide, flat bead that results in minimal metal dilution.

The pulsing action also reduces heat input by 20 to 80 amps compared to spray transfer. This produces less distortion and a smaller heat affected zone (HAZ). One application for pulsed spray transfer is for making critical welds on the high strength steel (HY80, HY100) used for submarine hulls, where mechanical properties cannot be degraded by excess heat.

Pulsed spray transfer permits out of position welding because there is no metal transfer during a portion of the cycle, thus giving the weld puddle a chance to freeze slightly. One company welding stainless steel switched from running flux cored wire to using solid wire with pulsed spray transfer. This allowed them to maintain high speeds in the flat position and weld in the vertical up position. The company was able to recoup its investment in the new pulsed welding equipment in four months by switching from flux cored to solid wire.

Pulsed spray GMAW is not a cure-all for every welding problem, nor can it provide all of the benefits mentioned above for every application. To determine if GMAW-P is right for you, work closely with your Miller distributor. Be sure to perform cost studies, develop welding procedures, and conduct trial runs to determine the feasibility of the process for your application.

GMAW-P is a modified spray transfer process that produces minimal spatter because the wire does not touch the weld puddle (with short circuit transfer, the wire touches the weld puddle approximately 180 - 220 times per second, creating spatter). In addition, pulsed spray transfer results in a more fluid weld puddle that wets out better. This produces better bead appearance, and it also permits higher travel speed.
source : http://www.welding.com/articles/bparticle7.htm

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Aluminations - Shedding light on aluminum welding issues

Frequency, or Hz, is the number of times the AC TIG arc switches between electrode negative and electrode positive in one second. Miller's Dynasty™ 300 DX inverter-based TIG power source permits adjusting output frequency from 20 to 250 Hz. Conventional TIG machines have a frequency fixed to that of the 60 Hz primary power.

Increasing the frequency narrows the shape of the arc cone and increases the arc force. This stabilizes the arc, reduces arc wandering and provides excellent directional control over the arc. On lap and T-joints, using a higher frequency lets you establish the weld puddle exactly at the root. This can ensure good penetration, control bead width and minimize the etched zone. With a 60 Hz output on fillet welds, the wider arc dances from plate to plate. The puddle starts at the toes of the weld and flows toward the center. On some joints, you're almost compelled to over-weld to ensure penetration at the root.
source : http://www.welding.com/articles/bparticle1.htm

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Surface Treatment Of Aluminum And Aluminum Alloys

Abstract:
Aluminum alloys are divided into two major categories: wrought and casting alloys. A further differentiation for each category is based primary on mechanism of property development. Many alloys respond to thermal treatment based on phase solubility. These treatments include solution heat treatment, quenching and precipitation, or age hardening.

In order to improve surface properties of final products, such as wear resistance, corrosion resistance, reflectivity etc., different types of surface treatment were designed. All of them are divided into several groups, such as electrochemical treatments, chemical treatments and coatings. In this article their terms and definitions will be explained.

Aluminum alloys are divided into two major categories: wrought and casting alloys. A further differentiation for each category is based primary on mechanism of property development. Many alloys respond to thermal treatment based on phase solubility. These treatments include solution heat treatment, quenching and precipitation, or age hardening.

In order to improve surface properties of final products, such as wear resistance, corrosion resistance, reflectivity etc., different types of surface treatment were designed. All of them are divided into several groups, such as electrochemical treatments, chemical treatments and coatings. In this article their terms and definitions will be explained.

Electrochemical treatment
Electrochemical brightening: Electrochemical treatment to improve the optical reflectivity of a surface.

Electropolishing: Polishing of a metal surface by making it anodic in an appropriate electrolyte.

Anodized metal Metal with an anodic coating, produced by an electrolytic oxidation process in which the metal is converted to a mainly oxide coating having protective, decorative or functional properties.

Clear anodized metal: Metal with a substantially colorless, translucent anodic oxidation coating.

Color anodized metal: Anodized metal colored either during anodizing or by subsequent coloring processes.

Integral color anodized metal: Metal that has been anodized using an appropriate (usually organic acid based) electrolyte which produces a colored coating during the anodizing process itself.

Electrolytically colored anodized metal: Metal with an anodic oxidation coating that has been colored by the electrolytic deposition of a metal or metal oxide into the pore structure.

Dyed anodized metal: Metal with an anodic oxidation coating colored by absorption of dye-stuff or pigments into the pore structure.

Combination color anodized metal: Metal with an anodic oxidation coating that is colored by electrolytic coloring or produced by integral color anodizing followed by absorption dyeing.

Interference color anodized metal: Metal with an anodic oxidation coating colored by means of optical interference effects.

Bright anodized metal: Anodized metal with a high specular reflectance as the primary characteristic.

Protective anodizing: Anodizing where protection against corrosion or wear is the primary characteristic and appearance is secondary or of no importance.

Decorative anodizing: Anodizing where a decorative finish with a uniform or a esthetically pleasing appearance is the primary characteristic.

Architectural anodizing: Anodizing to produce an architectural finish to be used in permanent, exterior and static situations where both appearance and long life are important.

Hard anodized metal: Anodized metal on which the anodic oxidation coating has been produced with wear and/or abrasion resistance as the primary characteristic.

Sealing: Treatment of anodic oxidation coatings on metal to reduce porosity and the absorption capacity of the coating by hydrothermal processes carried out after anodizing.

Cold impregnation: Treatment of anodic oxidation coatings on metal to plug the pores and reduce the absorption capacity of the coating by chemical processes carried out at low temperatures after anodizing.

Significant surface: The part of the product covered or to be covered by the coating and for which the coating is essential for serviceability and/or appearance.

Chemical treatment
Chemical brightening: Chemical treatment to improve the optical reflectivity of a surface.

Chemical polishing: Polishing of a metal surface by immersion in a solution of chemical reagents.

Degreasing: Removal of oil or grease, usually by a suitable organic solvent or an aqueous detergent.

Etching: Roughening of the surface of a metal by overall or selective dissolution in acid or caustic media.

Pickling: Removal of a thin surface layer of a metal by chemical action, mainly by treatment in a caustic solution.

Coating
Coating (organic): Method in which a coating material is applied on a metallic substrate. This process includes cleaning and chemical pre-treatment and either:

* one-side or two-side, single or multiple application of liquid or powder coating materials which are subsequently cured or
* laminating with plastic films.

Coil coating: Continuous coating of a metal strip.

Backing coat: Single coating of any type with no particular requirements for appearance, malleability, corrosion protection, etc. usually on the reverse side of the coated product.

Chemical conversion coating: Treatment of a metal with chemical solutions by dipping or spraying to build up an oxide film containing chromates or phosphates.

Priming: Application of a priming paint often pigmented with a corrosion inhibitor such as zinc chromate, after suitable pretreatment.

Pretreatment priming: Application of a solution containing a resin, a chromate and an acid, which is allowed to dry on and provide the key for subsequent painting.

Single coat system: Single coating either with requirements on appearance, malleability, corrosion protection, subsequent painting, etc., or as a primer with special properties regarding adhesion and corrosion protection for post-painting applications.

Multiple coat system: System comprising a primer or a base coat, possibly intermediate coat(s), and a top coat with particular requirements on appearance, malleability, corrosion protection, etc.

Organic coating: Dry paint film of the coated product or the organic film metal laminate.

Film coating: Organic film applied to a substrate to which an adhesive and, if appropriate, a primer has been applied beforehand.

Lacquering: Coating with a formulation based on a dissolved material which forms a transparent layer primarily after drying by evaporation of the solvent.
Painting: Coating with a non-transparent formulation containing pigments.
source :http://www.keytometals.com/Article67.htm

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Carburizing 1

Abstract:
Carburizing is the addition of carbon to the surface of low-carbon steels at temperatures generally between 850 and 950°C (1560 and 1740°F), at which austenite, with its high solubility for carbon, is the stable crystal structure. Hardening is accomplished when the high-carbon surface layer is quenched to form martensite so that a high-carbon martensitic case with good wear and fatigue resistance is superimposed on a tough, low-carbon steel core.
Carburizing steels for case hardening usually have base-carbon contents of about 0.2%, with the carbon content of the carburized layer generally being controlled at between 0.8 and 1% C. However, surface carbon is often limited to 0.9% because too high a carbon content can result in retained austenite and brittle martensite.


Carburizing is the addition of carbon to the surface of low-carbon steels at temperatures generally between 850 and 950°C (1560 and 1740°F), at which austenite, with its high solubility for carbon, is the stable crystal structure. Hardening is accomplished when the high-carbon surface layer is quenched to form martensite so that a high-carbon martensitic case with good wear and fatigue resistance is superimposed on a tough, low-carbon steel core.

Case hardness of carburized steels is primarily a function of carbon content. When the carbon content of the steel exceeds about 0.50% additional carbon has no effect on hardness but does enhance hardenability. Carbon in excess of 0.50% may not be dissolved, which would thus require temperatures high enough to ensure carbon-austenite solid solution.

Case depth of carburized steel is a function of carburizing time and the available carbon potential at the surface. When prolonged carburizing times are used for deep case depths, a high carbon potential produces a high surface-carbon content, which may thus result in excessive retained austenite or free carbides. These two microstructural elements both have adverse effects on the distribution of residual stress in the case-hardened part. Consequently, a high carbon potential may be suitable for short carburizing times but not for prolonged carburizing.

Carburizing steels for case hardening usually have base-carbon contents of about 0.2%, with the carbon content of the carburized layer generally being controlled at between 0.8 and 1% C. However, surface carbon is often limited to 0.9% because too high a carbon content can result in retained austenite and brittle martensite.

Most steels that are carburized are killed steels (deoxidized by the addition of aluminum), which maintain fine grain sizes to temperatures of about 1040°C. Steels made to coarse grain practices can be carburized if a double quench provides grain refinement. Double quenching usually consists of a direct quench and then a requench from a lower temperature.

Many alloy steels for case hardening are now specified on the basis of core hardenability. Although the same considerations generally apply to the selection of uncarburized grades, there are some peculiarities in carburizing applications.

First, in a case-hardened steel, the hardenability of both case and core must be considered. Because of the difference in carbon content, case and core have quite different hardenabilities, and this difference is much greater for some steels than for others.

Moreover, the two regions have different in-service functions to perform. Until the introduction of lean alloy steels such as the 86xx series, with and without boron, there was little need to be concerned about case hardenability because the alloy content combined with the high carbon content always provided adequate hardenability. This is still generally true when the steels are direct quenched from carburizing, so that the carbon and alloying elements are in solution in the case austenite. In parts that are reheated for hardening and in heavy-sectioned parts, however, both case and core hardenability requirements should be carefully evaluated.

The relationship between the thermal gradient and the carbon gradient during quenching of a carburized part can make a measurable difference in the case depth as measured by hardness. That is, an increase in base hardenability can produce a higher proportion of martensite for a given carbon level, yielding an increased measured case depth. Therefore, a shallower carbon profile and shorter carburizing time could be used to attain the desired result in a properly chosen steel.

Core Hardness. A common mistake is to specify too narrow a range of core hardness. When the final quench is from a temperature high enough to allow the development of full core hardness, the hardness variation at any location will be that of the hardenability band of the steel at the corresponding position on the end-quenched hardenability specimen.

In standard steels purchased to chemical composition requirements rather than to hardenability, the range can be 20 or more HRC points; for example, 8620 may vary from 20 to 45 HRC at the 4/16 in.(6.35mm) position. The 25-point range emphasizes the advantage of purchasing to hardenability specifications to avoid the intolerable variation possible within the ranges for standard chemistry steels. Another way to control core hardness within narrow limits without resorting to the use of high-alloy steels is to use a final quench from a lower temperature so that full hardness in the case will be developed without the disadvantage of excessive core hardness.

Gears are almost always oil quenched because distortion must be held to the lowest possible level. Therefore, alloy steels are usually selected, with much debate about which particular alloy. The lower-alloy steels such as 4023, 5120, 4118, 8620, and 4620, with a carbon range between 0.15 and 0.25%, are widely used and generally satisfactory. Usually, the first choice is one of the last two steels mentioned, either of which should be safe for all ordinary applications. The final choice, based on service experience or dynamometer testing, should be the least expensive steel that will do the job. For heavy-duty applications, higher-alloy grades such as 4320, 4817, and 9310 are justifiable if based on actual performance tests. The life testing of gears in the same mountings used in service to prove both the design and the steel selection is particularly important.

In other applications, when distortion is not a major factor, the carbon steels described above, water quenched, can be used up to a 50 mm (2 in.) diameter. In larger sizes, low-alloy steels, water quenched, such as 5120, 4023, and 6120 can be used, but possible distortion and quench cracking must be avoided.

Carburizing Methods. While the basic principle of carburizing has remained unchanged since carburizing was first employed, the method used to introduce the carbon into the steel has been a matter of continuous evolution.

In its earliest application, parts were simply placed in a suitable container and covered with a thick layer of carbon powder (pack carburizing). Although effective in introducing carbon, this method was exceedingly slow, and as the demand for greater production grew, a new process using a gaseous atmosphere was developed.

In gas carburizing, the parts are surrounded by a carbon-bearing atmosphere that can be continuously replenished so that a high carbon potential can be maintained. While the rate of carburizing is substantially increased in the gaseous atmosphere, the method requires the use of a multicomponent atmosphere whose composition must be very closely controlled to avoid deleterious side effects, for example, surface and grain-boundary oxides. In addition, a separate piece of equipment is required to generate the atmosphere and control its composition. Despite this increased complexity, gas carburizing has become the most effective and widely used method for carburizing steel parts in large quantities.

In efforts required to simplify the atmosphere, carburizing in an oxygen-free environment at very low pressure (vacuum carburizing) has been explored and developed into a viable and important alternative. Although the furnace enclosure in some respects becomes more complex, the atmosphere is greatly simplified. A single-component atmosphere consisting solely of a simple gaseous hydrocarbon, for example methane, may be used. Furthermore, because the parts are heated in an oxygen-free environment, the carburizing temperature may be increased substantially without the risk of surface or grain-boundary oxidation. The higher temperature permitted increases not only the solid solubility of carbon in the austenite but also its rate of diffusion, so that the time required to achieve the case depth desired is reduced.

Although vacuum carburizing overcomes some of the complexities of gas carbunzing, it introduces a serious new problem that must be addressed. Because vacuum carburizing is conducted at very low pressures, and the rate of flow of the carburizing gas into the furnace is very low, the carbon potential of the gas in deep recesses and blind holes is quickly depleted. Unless this gas is replenished, a great nonuniformity in case depth over the surface of the part is likely to occur. If, in an effort to overcome this problem, the gas pressure is increased significantly, another problem arises, that of free-carbon formation, or sooting.

Thus, in order to obtain cases of reasonably uniform depth over a part of complex shape, the gas pressure must be increased periodically to replenish the depleted atmosphere in recesses and then reduced again to the operating pressure. Clearly, a delicate balance exists in vacuum carburizing: The process conditions must be adjusted to obtain the best compromise between case uniformity, risk of sooting, and carburizing rate.

A method that overcomes both of these major problems, yet retains the desirable features of a simple atmosphere and permissible operating temperature is plasma or ion carburizing.

To summarize, carburizing methods include:

* Gas carburizing
* Vacuum carburizing
* Plasma carburizing
* Salt bath carburizing
* Pack carburizing

These methods introduce carbon by the use of gas (atmospheric-gas, plasma, and vacuum carburizing), liquids (salt bath carburizing), or solid compounds (pack carburizing). All of these methods have limitations and advantages, but gas carburizing is used most often for large-scale production because it can be accurately controlled and involves a minimum of special handling.

Vacuum carbunzing and plasma carburizing have found applications because of the absence of oxygen in the furnace atmosphere. Salt bath and pack carburizing arc still done occasionally, but have little commercial importance today.

Process characteristics of the above-mentioned carburizing methods fall into two general groups:

* Conventional methods, which introduce carbon by gas atmospheres, salt baths or charcoal packs
* Plasma methods, which impinge positive carbon ions on the surface of a steel part (the cathode)

The main difference between conventional and plasma methods is the reduced carburizing times achieved in plasma-assisted methods. The quickly attained surface saturation also results in faster diffusion kinetics. Furthermore, plasma carburizing produces very uniform case depths, even in parts with irregular surfaces.

With the conventional methods, carburization always takes place by means of a gaseous phase of carbon monoxide; however, each method also involves different reaction and surface kinetics, producing different case-hardening results.

In general, with conventional methods, carbon monoxide breaks down at the steel surface:

2CO ↔ CO2 + C

The liberated carbon is readily dissolved by the austenite phase and diffuses into the body of the steel. For some process methods (gas and pack carburizing), the carbon dioxide produced may react with the carbon atmosphere or pack charcoal to produce new carbon monoxide by the reverse reaction.

Carburizing is most frequently performed between 850 and 950°C (1550 and 1750°F), but sometimes higher temperatures are used to reduce cycle times and/or produce deeper depths of the high-carbon surface layer.

A comprehensive model of gas carburization must include algorithms that describe:

* Carbon diffusion
* Kinetics of the surface reaction
* Kinetics of the reaction between endogas and enriching gas
* Purging (for batch processes)
* The atmosphere control system.

source :http://steel.keytometals.com/Articles/Art114.htm

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Carburizing 2

Carburizing is a process of adding Carbon to the surface. This is done by exposing the part to a Carbon rich atmosphere at an elevated temperature and allows diffusion to transfer the Carbon atoms into steel. This diffusion will work only if the steel has low carbon content, because diffusion works on the differential of concentration principle. If, for example the steel had high carbon content to begin with, and is heated in a carbon free furnace, such as air, the carbon will tend to diffuse out of the steel resulting in Decarburization.

Pack Carburizing: Parts are packed in a high carbon medium such as carbon powder or cast iron shavings and heated in a furnace for 12 to 72 hours at 900 ºC (1652 ºF). At this temperature CO gas is produced which is a strong reducing agent. The reduction reaction occurs on the surface of the steel releasing Carbon, which is then diffused into the surface due to the high temperature. When enough Carbon is absorbed inside the part (based on experience and theoretical calculations based on diffusion theory), the parts are removed and can be subject to the normal hardening methods.

The Carbon on the surface is 0.7% to 1.2% depending on process conditions. The hardness achieved is 60 - 65 RC. The depth of the case ranges from about 0.1 mm (0.004 in) upto 1.5 mm (0.060 in). Some of the problems with pack carburizing is that the process is difficult to control as far as temperature uniformity is concerned, and the heating is inefficient.

Gas Carburizing: Gas Carburizing is conceptually the same as pack carburizing, except that Carbon Monoxide (CO) gas is supplied to a heated furnace and the reduction reaction of deposition of carbon takes place on the surface of the part. This processes overcomes most of the problems of pack carburizing. The temperature diffusion is as good as it can be with a furnace. The only concern is to safely contain the CO gas. A variation of gas carburizing is when alcohol is dripped into the furnace and it volatilizes readily to provide the reducing reaction for the deposition of the carbon.

Liquid Carburizing: The steel parts are immersed in a molten carbon rich bath. In the past, such baths have cyanide (CN) as the main component. However, safety concerns have led to non-toxic baths that achieve the same result.

source : http://www.efunda.com/processes/heat_treat/hardening/diffusion.cfm#PageTop

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