Rabu, 25 Februari 2015

Cold crack of line pipe welding

Cold crack of line pipe welding - Cold crack is a serious flaw which may arise in the process of line pipe welding. Cold cracking generally appears during the cooling process, near the martensitic transformation start temperature Ms point or below the temperature range, and more occurs below 100 . Cold cracks can appear immediately after welding, or often emerges over time, and thus tend to have delayed cold cracking characteristics.

Cold crack of line pipe welding


Mass of practical and theoretical production studies have shown that the tendency of hardened steel, hydrogen content and stress distribution in welded joints and welded joints are the three main factors that cold cracking appearing when welding pipeline. So, in essence, welding cold cracks induced embrittlement.
Because HAZ has a larger hardening tendency and gap effect, so cold cracks occurs mainly in the pipeline of the heat affected zone. Meanwhile, the cold cracks may also occur in the weld. Cold cracks are often generated at grain boundaries, with a large number of expansion along the grain, but sometimes also be extended along the grain boundaries.
Pipeline pipe molding usually low hydrogen weld double submerged arc welding method(lsaw steel pipe and ssaw steel pipe), meanwhile the welding heat input is relative great, the cooling speed after welding is lower than spot ring welding. And the heat affected zone is not easy to appear organize with high hardness, so cold crack infrequently appears.
Pipeline spot welding mostly uses thin ring cellulose SMAW, easily lead to penetrating of large amount of hydrogen, meanwhile low heat input, cooling faster, easier to produce high hardness, low toughness low temperature transformation productsBusiness Management Articles, thereby increasing the cold crack sensitivity.
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Kamis, 12 Februari 2015

Welding Tools

Welding Tools - Don't ignore the importance of the protection welding tools which are a sine-qua-non condition for all welding activity. The main welding tools meant to ensure the safety of the process include helmets, goggles, masks and hoods with auto-darkening specificity, and other head gear that could vary from one case to the other. Always try to purchase those welding tools that are adjustable to different combinations, particularly if you have an extended field of welding activity. Setting variables is important, and even if such equipment is more expensive than the standard one, it is definitely worth the effort.Before buying any welding tools, have a look at the profile virtual shops to check for product features and compare prices. You'll be surprised to see what a rich offer of products you can find online, at prices that range from low and moderate to incredibly high. Besides the catalogs, many companies also offer consultancy to interested clients; there are presentations of the welding tools, and for each of them you may ask for further details. In case price is not a problem, and you're only after quality, it is good to choose the companies with a longer experience in the welding tools business.Welding tools catalog request is also possible with some companies that promote their products online, which will give you the general picture of what else you could buy to improve the quality of your welds. For those interested in the informational dimension of welding tools sites, there are even online histories of the hardware equipments. Periodical technical evaluation of the machines and equipments is also a rule of the thumb in the welding businessPsychology Articles, it is a basis condition for the well development of the welding process in the safest of conditions as it protects not just the human element but your investment as well.



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Jumat, 06 Februari 2015

Fusion metal welding

Welding – is a fabrication method to get indestructible join of separate materials. There are many and very different welding processes and methods. Fusion welding is widely applied in industry, agriculture, construction and other areas. In addition to arc welding, also apply to contact, gas, pressure, thermal, inductive, laser welding and other methods.
The greatest impact on welding has metal chemical composition. Carbon steel that contains up to 0.35% carbon is welded well by all means. If steel has up to 1.0-1.5% silicon or manganese, welding is not compromised, but the growing share of these impurities makes welding increasingly difficult.

Electric arc metal welding

When welding with electric arc, metal edges are melted by an electric arc. Aid seam forms a melted
metal. In order to create the arc, it is necessary to ionize the gas. To this purpose, the metal electrode is touched to metal. The short circuit starts when metal contact spot heats up, begins to emit electrons, which are ionizing close to the air, and away from the metal electrode arc occurs. Electric Arc - a long-lasting electric-discharge in gas environment. The arc voltage depends on the arc length and the spray density. Welding manually spray density is small, welding arc length is 2-6 mm and the required voltage is 10-20 volts. For fusion welding most commonly used fusible welding electrodes, consisting of metal bars, coating improve arc stability and metal to protect the environment, the atmosphere effect. Electrode in a molten metal entrained drops.

Arc melted electrode metal in the form of small droplets moving in the welding metal crater, the process continually repeats itself, the proposed results. Using the filament electrode the arc is burning between the metal edges of the electrode is fed with added wire, which melts at the temperature and shape seam.

Droplet size depends on the strength of the spray. At the same electrode diameters, growing current, a drop in its decline, and growing tension - increasing to it. Better proposed to come when a small drop. Therefore in order to obtain good welding seam must boil a short arc, low arc voltage and current selection of the
drops are small.

To produce welding electrodes witch are used to fill the welding grove, which produces in accordance with the relevant standards. Wire Mark - a metallic chemical composition, which is approximately equivalent to welded metal brand. Welding is used more refined metal from harmful impurities (sulfur, phosphorus), and has increased impurity content. Wire is produced 0,3-12 mm. Wire must be clean, it is considered dry, delivered in rolls (roll one piece). The most common fusible electrodes. Produced and unaccompanied electrodes from tungsten, graphite, carbon.
Welding as a specific technological process used in many industries - energyPsychology Articles, construction and other fields. In this article I am going to overview general welding process. For more relevant info please check other my articles
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Rabu, 04 Februari 2015

What to know in welding

This is what we are going to discuss.  It is a known fact that Welding is a sculptural process that joins two metals by the process of welding and Weldor is a man who does the welding process. Compared to other industrial jobs, welding is fairly dangerous and the occupational and health hazards of welding can be avoided with proper equipment, safe materials, and a few common sense measures. Welding tools and welding equipment are essential in welding services and the manufacturing industries fail to meet the demands, if there are no proper welding tools and welding products.
The process of welding was there from 310 AD itself and the first welding process introduced was forge welding, and later on many welding processes were introduced to weld different types of metals.  From the decade, welding has developed a lot and new welding technologies with advanced welding equipment and systems have been introduced. Historical monuments, construction of building, bridges, ship building, automobile, aerospace, power plants, refineries and all manufacturing activities need the process of welding. 20th century started good for the welding process because it saw many new welding processes and technologies.

Stick welding, tig welding and mig welding are the welding process that is used frequently in welding industries.  All these welding equipment needs the appropriate welder machines and the welder machine is an equipment that is used to make weld. The arc welding process is categorized into two types depends upon the usage of its consumables.  The mig welding comes under the consumable electrode method whereas tig welding comes under the non consumable electrode method.  The tig welding use the tungsten electrode as its consumables and by using this process, steel, aluminum, magnesium and copper alloys are welded.

Stick welding method is primarily used to weld iron and steels. Mig welding process is originally developed to weld aluminum, but later on it is used to weld steels. Different types of welder machines are available such as mig welder, tig welder, on board welder, reconditioned welder, aluminum welder, steel welder and metal welder can be used for the process of welding. Consumables available for welding are tig consumables, mig consumables, plasma cutter consumables, tungsten consumables and welding accessories are the tools that are attached to welding machines, and it is used for the better performance of welding.

Modernization is what most of the welding products is, on roll capacity of wires, extended wires, portability and compatibility is its features. These welders machine can be typically used in all industrial applications from light fabrication to aerospace. Welding accessories such as foot pedal, air regulator, ground clamp and argon regulator are essential to support the welder machines. For the weldor’s safety, each and every industries should be equipped with welding gears such as welding helmetsScience Articles, welding clothes welding goggles and welding gloves for the safety of the weldor.

The manufacturing industries should be aware of all the welding tools and welding equipment for the better development of their industries.



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Selasa, 03 Februari 2015

All About Mig Welding

All About Mig Welding - Metal inert gas (MIG) welding is a method of joining two or more pieces of metal together using equipment that is different from more traditional welding gear. MIG welding creates an arc of electricity between a conductive wire at the end of the welding torch and the pieces of metal that are being welded. The heat of the electrical arc melts the metal and the conductive wire that is coming out of the end of the welding torch. This creates a strong weld between the pieces but consumes the conductive wire, which must be constantly fed through the welding nozzle as work is performed.
The Advantages of MIG Welding

MIG welding has several benefits over other types of welding. The head of the welding nozzle distributes a layer of gas around the area being welded. This inert or semi-inert gas protects the weld point from contamination by particles that could be carried in the air. This results in a very clean weld. The technique that is required to perform MIG welding also helps to create a firm bond with a minimal amount of debris and splatter. MIG welding is not like traditional welding, however, and a MIG welding course is required to correctly use the tools.

The Disadvantages of MIG Welding

MIG welding training can be difficult for individuals who are used to traditional gas or stick welding. The welding torch must be moved in the opposite direction and the automatically fed wire can be frustrating to manage. Since MIG welding uses a protective gas barrier, welding cannot be performed outdoors or in areas with turbulent winds. MIG welding also requires that objects that are worked on are electrically grounded. This can be a problem for those without MIG welding training and can lead to damaged equipment and potentially serious injuries.

Primary Uses for MIG Welding

MIG welding is known for being a very flexible type of gas metal arc welding. It is also very fast compared to some other types of welding. MIG welding is often used in automated processes such as the production of automobiles and car parts because it is predictable and consistent. It is also used for the repair of metal structures, car parts and metal piping. The compact nature of the machine and the relative ease of a MIG welding course have made it very popular for hobbyists and other home uses. Overall, MIG welding is the most common type of modern welding that is used across nearly all industries.
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