SMAW: The lowdown on the lingo

WWW.THEFABRICATOR.COM JULY 2012

July 25, 2012

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Welding novices might be confused by terminology commonly used by fellow welders but not found in standard glossaries. This article defines some of these terms used in shielded metal arc welding.

SMAW welding

From keyhole to downhill to arc blow, the lingo associated with SMAW is a common occurrence you may encounter in the process.

When it comes to shielded metal arc welding (SMAW), following formal welding procedures is critical to achieving quality results and meaningful productivity. The way welding operators speak about the process, however, isn’t always so formal. Lingo related to equipment, technique, arc characteristics, and more is common throughout the industry. In many cases, you won’t find these definitions in your standard welding glossary. Still, they are a prevalent part of the culture of welding.

The following are some terms and their definitions to help you navigate your way through the lingo.

Weld Beads and Pools

It’s not surprising that so much of the lingo relates to the weld and the weld pool. After all, they are at the core of the process. Here are some terms you may encounter on the job site.

Stringer bead
A narrow, straight weld bead that is created by moving the SMAW electrode straight along the weld joint. A quality stringer bead should have good tie-in on both sides of the weld.
Wetting-out
The ability of a weld puddle to flow evenly, allowing both sides of the weld to merge smoothly with the base material.
Root pass
The first weld bead placed in the weld joint in a multipass weld.
Fill
Also referred to as a fill pass, it is the amount of weld bead necessary to fill the weld joint. This pass comes after the root pass and before the cap pass (see next term). In some applications, multiple fill passes are necessary.
Cap
The final weld bead in a weld joint. It may be completed in the form of a stringer bead or by a weaving motion back and forth. 
Fisheye
The shape of the puddle while welding.It is sometimes also used to describe the shape of the crater at the end of the weld.
Keyhole
The shape of the hole that is formed while welding an open-root joint, particularly with an AWS 6010 SMAW electrode. It allows for good penetration and tie-in in the completed weld.

The Arc

Arc characteristics are important in any welding process. These allow you to determine the correct travel speed and motion, or method of moving, the SMAW electrode to gain the desired results. The following terms all refer to the arc or technology used to adjust the arc for improved performance.

Stiff
An arc that provides a lot of drive (dig) into the weld joint. It often is associated with increased spatter.
Soft
An arc that has less drive (dig) and potentially less penetration into the weld joint.
Dig
Also called arc force or arc control. It is the ability to adjust the drive of the SMAW electrode to achieve more or less penetration into the weld joint.
Arc control
The ability to adjust the amount of dig for the best weld result. It also refers to the technology that provides the power source with additional amperage during low-voltage (short arc length) conditions. In this case, it helps you avoid “sticking” the SMAW electrode when a short arc length is used.
Hot start
Function used on some SMAW power sources to simplify arc starting when using difficult-to-start electrodes. It works by adding more current to help establish the arc.
Arc blow
The deflection of the arc away from the direction of travel caused by either magnetic or thermal influences. For example, as the weld gets closer to the end of a plate, it may deflect to one side, forward, or backward, which typically causes heavy spatter and undercutting. Arc blow caused by magnetic buildup also is referred to as arc wander.

Techniques

Creating quality welds with the SMAW process requires special attention to welding parameters and procedures. It also demands attention to various welding positions.  Across various industries, the following are some common related terms you may encounter.

Downhill
The technique of creating a weld in a vertical-down progression; that is, from top to bottom of the weld joint.
Uphill
The technique of creating a weld in a vertical-up progression; that is, from bottom to top of the weld joint.
Weave
Also referred to as oscillating or stitching. It is the technique of moving the SMAW electrode from side to side in order to wash the sides of the weld pool into the base material.

Weld Defects

Weld defects are an unfortunate reality in any welding process – and ones that proper technique and adherence to welding parameters can help prevent. Some in the industry call common weld defects by these terms. 

Cold lap
A defect that occurs when there is lack of penetration on one leg of the weld. Also called lack of fusion or incomplete fusion, it most often is caused by travel speeds that are too slow or weaves that are too wide. It also can be caused by lack of heat input, which prevents the weld and base metal from fusing together.
Undercut
A weld defect in which the base material overhangs the weld bead. It appears as a groove or crater near the outer edges of the weld and often results from voltage that is too high or using an incorrect weld angle.
Wagon tracks
Also called worm tracking, this weld defect is caused by hydrogen that has been trapped by the freezing slag. The defect, typically the result of excessive voltage, appears when a bubble flows into the weld puddle and evaporates into the atmosphere.

Equipment

You can’t get the job done without the proper equipment. And even though most of the focus is on the power source, other components play an important part in the SMAW process too.

Stinger
Another name for the SMAW electrode holder, it comes in various sizes for light- to heavy-duty welding applications.
Whip
The cable—typically 10 to 15 ft. long—that is connected to the SMAW electrode holder, or stinger.

Electrodes

SMAW electrodes come in various diameters and alloys to meet the needs of differing base materials and industry applications.  Each has its own unique arc and burn-off characteristics.

Rods
An informal term for a SMAW electrode.
Cellulosic
SMAW electrodes having organic material, such as paper, as the main component. These electrodes tend to have deep penetrating capabilities.
Low hydrogen
SMAW electrodes that provide weld deposits containing a low amount of hydrogen gas, typically 4 to 8 ml per 100 g of weldment. The low amounts of hydrogen help minimize cracking in the completed weld.
Fingernail
The shape of the SMAW electrode as the flux burns off the end.
Unloading
The way a SMAW electrode, typically an AWS 7018 classification, burns off while welding.It occurs as a large amount of the SMAW electrode releases across the arc, often resulting in additional spatter.

Keeping up with SMAW lingo isn’t critical to achieving good welds; rather, following proper procedures, practice, and careful attention to technique are critical. However, knowing some of the common lingo welders use can help you communicate effectively with others and avoid confusion on the job.



Joe Gitter

Product Manager
Miller Electric Mfg. Co.

Bruce Morrett

Contributing Writer

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