I-CAR AWQT flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

GMAW shade selection

Match filter shade to arc current: shade 7 below 60 A, shade 10 for 60-160 A, shade 11 for 160-250 A, and shade 12 or 13 above 250 A.

Metal fume fever

Flu-like illness caused by breathing zinc oxide fume when welding galvanized steel. Local exhaust ventilation and respiratory protection are required.

Hot work fire watch

Remove combustibles within about 11 m (35 ft) of the arc and post a fire watch during welding and for at least 30 minutes afterward.

Short-circuit transfer

Low-current GMAW mode where the wire repeatedly touches the puddle and pinches off. Used on thin steel with CO2 or argon/CO2 mix.

Spray transfer

High-current GMAW mode using argon-rich gas where fine droplets transfer axially. Produces deep penetration and is limited to flat positions.

Wire feed speed vs voltage

Wire feed speed controls current and penetration; voltage controls arc length and bead shape. Adjust one at a time when tuning.

Contact-tip-to-work distance

Distance from contact tip to work should be about 10-15 mm (3/8-5/8 in). Longer stick-out reduces current and penetration.

GMAW duty cycle

Percentage of a 10-minute period a machine can weld at rated output. A 60% rating at 200 A allows 6 minutes welding and 4 minutes cooling.

I squared R heating

STRSW heat equals current squared times resistance times time. Contact resistance at the faying surface drives nugget formation between the electrodes.

STRSW squeeze and hold

Electrode force is applied before current (squeeze), maintained during weld time, and held briefly after current stops to forge the nugget.

Shunting in spot welding

Current bypasses the intended weld through an adjacent weld or conductive path. Space welds per OEM distance, often about 25 mm or more.

STRSW nugget diameter rule

Common acceptance minimum is about 4 times the square root of the thinner sheet thickness in millimeters, subject to the OEM specification.

Silicon bronze wire

CuSi3 filler with a melting range near 950-1000 C, well below steel, so the base metal is not melted during brazing.

MIG brazing gas

Pure argon or argon-rich shielding gas is used for silicon bronze. CO2-rich mixes can oxidize the wire and are generally avoided.

Brazing travel technique

Use a push or forehand technique with a short arc and slight drag angle; the puddle should wet and flow without digging into the base metal.

Brazing strength limitation

Silicon bronze is weaker than steel weld metal. It is not a structural substitute unless the OEM procedure explicitly allows it.

Mild steel weldability

Low-carbon steel welds easily with GMAW and STRSW. Its low carbon and good ductility make the heat-affected zone forgiving.

AHSS heat sensitivity

Advanced high-strength steels, especially martensitic and boron grades, are highly heat sensitive and may require OEM-specific joining or be non-weldable.

Galvanized coating effect

Zinc vaporizes at welding temperature, causing porosity and fume. Remove coating near the weld or follow OEM-approved procedures.

Steel identification methods

Use OEM repair information, build sheets, panel markings, magnet tests for ferrous versus non-ferrous, and hardness or spark testing.

Aluminum oxide removal

Aluminum oxide melts near 2050 C versus 660 C for the base metal. It must be removed mechanically before welding to allow fusion.

Aluminum push technique

Push the gun with a 10-15 degree travel angle and short arc using pure argon and DCEP polarity for aluminum GMAW.

Aluminum filler selection

ER4043 and ER5356 are common aluminum fillers. ER5356 offers higher strength and better color match where required.

Aluminum-to-steel joining

Direct fusion welding is not acceptable. Use OEM-approved self-piercing rivets, flow-drill screws, or structural adhesives instead.

Undercut defect

A groove melted into the base metal at the weld toe and left unfilled. It reduces section thickness and is a common rejection reason.

Incomplete fusion

A cold lap where weld metal fails to bond to base metal. Often hidden, it is a serious structural defect caused by low heat or contamination.

STRSW visual inspection

Check nugget diameter, indentation depth, and surface discoloration. Excessive indentation or expulsion indicates incorrect weld parameters.

Brazed joint inspection

Look for full joint fill, smooth wetting, and no gaps or porosity. A cold, lumpy bead indicates insufficient heat.

Chisel peel test

Standard destructive STRSW check. A chisel is driven between panels and the weld pried apart to expose and measure the nugget.

Plug button test

The weld should pull a plug from one panel rather than separate at the interface. Interfacial separation indicates insufficient heat input.

Bend test on coupon

A sound GMAW weld bends without cracking. Lack of fusion or porosity opens during bending, revealing hidden defects.

OEM procedure priority

The OEM repair procedure governs when it conflicts with generic guidance. Do not proceed on structural parts without the correct procedure.