Posts Tagged ‘Shield Metal Arc Welding’

The GMAW process (part 1):

Thursday, August 18th, 2011

One of the most widely misunderstood forms of welding is GMAW. Gas Metal Arc Welding is more commonly known as MIG. MIG is an older term used to refer to Metal Inert Gas(MIG) welding. Originally it was created to refer generically to a gas shielded form of welding with a semi- automatically fed solid filler wire wrapped on a roll. But as the “correct” police came about in an effort to clarify the science of welding, the MIG acronym was retired from official use to reflect a more accurate definition. Although the term is still widely accepted, the term “MIG did not allow for the fact that Carbon Dioxide, and to a lesser extent Oxygen is almost always used as a mixed component of the shielding gas, making it partially “active”, rather than “inert”. This led to the splinter definition of MAG: Metal Active Gas. So the GMAW banner accurately describes both types of operation.

GMAW

GMAW

To make matters worse, many people often confuse MIG with other forms of wire welding such as Flux Core which though may use the same or similar equipment, is an entirely different process. Flux core uses a hollow wire loaded with a flux that is used in place of the shielding gas that rises to the top of the weld pool and protects the metal while it is cooling. The gas is not used. Another form of wire welding that leads to further confusion is the dual-shield form of wire welding, which uses both a gas and a special flux cored wire to shield the weld.

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The SMAW process (part 2):

Wednesday, August 17th, 2011

The bare metal portion of the rod that is not coated is inserted into an electrode holder, sometimes called a “stinger”. The stinger holds the metal rod while welding and allows the weldor, (the person), to change the angle of the rod without having to change position or to reach around an object to weld.

The arc is struck by lightly tapping the electrode, (after inserting it into the stinger of course!), on the metal, or alternately flicking the electrode along the metal like a match. Of course, you must confine your arc striking to the immediate weld area or risk defects resulting in weld failure or rejection by an welding inspector, if you are required to submit your weld in a professional setting. As the arc is struck the electrode must be held slightly off the metal in most cases to maintain the arc and to deposit the filler metal into the weld, blending both pieces of base metal into the weld. While welding the welding rod is gradually consumed and deposited into the metal. The rod must be manually adjusted to keep the arc gap consistent. This means the rod is constantly fed closer to the puddle as it melts. It takes practice to manage this arc gap and to prevent contamination of the weld.

SMAW

SMAW

Even though Shielded Metal Arc Welding is largely a manual process it is a very sound and safe form of welding. It is also considered the most versatile and widely adapted form of welding, allowing extreme portability, while also allowing the weldor to competently weld virtually any thickness, even with smaller welders, given enough time and patience. If you’re thinking that stick welding may be what you are looking for, Everlast offers a full line of IGBT based inverter stick welders in our full line of PowerARC welders, from 140 amp to 400 amps that can manage the smallest homeowner chore to the largest industrial task. Inverters offer compact size with reduced power consumption over the heavy power hungry transformer Stick welders.

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The SMAW Process (part 1):

Tuesday, August 16th, 2011

We’ll start with our look at welding definitions by discussing one of the most common welding processes: SMAW. SMAW stands for Shielded Metal Arc Welding. It’s also commonly referred to as Stick welding, or generally as Arc welding. (This latter term can loosely apply to other forms of welding). Stick welders use a metal welding electrode as a filler material, to join the two pieces of metal together using an electric arc to heat and melt the metal into a puddle that gradually solidifies. Also called a welding rod, this metal cored electrode is usually some form of steel or stainless steel with a flux surrounding the electrode. The flux is a hard, coating that surrounds the rod down most of the length. While welding this flux serves several purposes.

SMAW

SMAW

1) To “shield” and protect the metal while welding, preventing oxygen from the atmosphere getting to the white hot metal and rapidly oxidizing the weld. An oxidized weld is weak and porous.

2) To help clean the metal and remove contaminants from the weld. As the flux interacts with the molten metal it helps to “float” out impurities. Flux components vary, while some welding rods have an iron powder base, others may have a cellulose base, all with trace amounts of other minerals or metals to form protective cocktail.

3) To provide a certain welding characteristic. Some electrodes due to their flux type weld more smoothly than others. Some because of their flux, cool more rapidly and penetrate more deeply. 

Welding electrodes are available in a variety of sizes, and purposes. After completing the weld and the weld has sufficiently cooled, the slag (consumed flux that lies on top of the weld) must be removed via chipping or a wire brush.

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Shielded Metal Arc Welding (SMAW) Is A Flexible Welding Process:

Tuesday, December 21st, 2010

Shielded metal arc welding (SMAW) is one of the most widely used welding processes among welders due to its low cost, flexibility, portability and usefulness. Machines and electrodes that are used over here are of low cost. The device itself can be as simple as a 110-volt, step down transformer. Electrodes are available from a large number of manufactures in various sizes of packages.

The SMAW procedure is a very flexible kind of welding process. In this process you get a chance to weld metal of any thickness and additionally you can also weld them in various positions.

Shielded metal arc welding process is a very portable kind of process for the reason that it is very easier to move the equipments. In this kind of weld, engine-driven generator type welders are also available. Moreover the limited amount of equipment that is required for the process makes moving process easier.

Shielded metal arc welding is ingenious and it can be used for welding almost any kind of metal or alloy, including cast irons, aluminium, stainless steel and nickel. The flexibility of the process allows metal of any thickness to be welded in any position.

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Speed of Travel for Shield Metal Arc Welding

Thursday, April 29th, 2010

One of the important things that you will have to see while performing a shield metal arc welding is the speed of travel. You will have to keep in mind that its importance as the appropriate travel speed creates a weld bead with the preferred contour or crown width as well as the neat look with perfect finish. You might have to fine-tune the travel speed so as to make the arc stay within the one-third of the weld pool.

When the travel speed is slow, it produces wide, turned in bead along with a shallow diffusion. On the other hand extremely high travel speed also decreases the penetration creating a thin or extremely crowned bead, as well as undercuts in a few cases.

Another tip to improve your welding is to always get a good view of the weld puddle. Or else you won’t be able to be sure that you are welding the joint. Keep your head off to the side f the smoke so that your sight doesn’t get disturbed.

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