AWS Certified Welder flashcards

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

SMAW electrode E7018

A low-hydrogen, iron-powder, covered electrode with 70,000 psi minimum tensile strength, usable in all positions, and requiring dry storage to prevent hydrogen cracking.

Spray transfer GMAW

A metal-transfer mode using high current and an argon-rich gas that produces fine droplets and deep penetration; it is limited to flat and horizontal positions.

GTAW AC for aluminum

Alternating current alternates cleaning (electrode-positive) and penetration (electrode-negative) half-cycles, breaking the aluminum oxide layer while limiting tungsten overheating.

Self-shielded FCAW

A flux-cored process whose electrode contains its own shielding ingredients, so it needs no external gas and resists wind better than gas-shielded processes.

Submerged arc welding

An arc process covered by granular flux that shields the arc and metal; it gives high deposition but is limited to flat and horizontal positions.

Heat input formula

Heat input in kJ/in equals voltage times amperage times 60, divided by travel speed in inches per minute times 1000.

Carbon equivalent

A formula combining carbon and alloying elements (Mn, Cr, Mo, V, Ni, Cu) to estimate hardenability; higher values require preheat and low-hydrogen practice.

Electrode tensile digits

In an EXXYY classification, the first two digits give minimum tensile strength in ksi, so E70 electrodes deposit at least 70,000 psi tensile strength.

Flat position 1G

Welding from above with the joint axis horizontal; gravity holds the puddle in the joint, giving the highest deposition and easiest control.

Horizontal position 2G

The weld axis is horizontal but the joint face is vertical; the puddle tends to sag, so lower current and a slight weave are used.

Vertical uphill welding

Progressing upward in the 3G position with higher current and a slight weave; it gives deeper penetration but slower travel than downhill.

Overhead position 4G

Welding from below the joint; gravity pulls the puddle away, so lower current, a short arc, and faster travel are needed.

6G pipe position

A fixed pipe inclined at 45 degrees with no rotation; the welder must weld in all positions, making it the most demanding pipe qualification.

5G pipe position

A fixed pipe with a horizontal axis that is not rotated; the welder moves around it, covering flat, vertical, and overhead sections.

Vertical-down welding

Progressing downward in the vertical position; it is fast and gives shallow penetration, so it is generally limited to thin sheet and specific electrodes.

Position qualification range

A test in a more difficult position, such as 6G or 4G, usually qualifies the easier positions within the range allowed by the standard.

AISI 1018 steel

A low-carbon steel (about 0.18% carbon) that welds readily with minimal preheat and is common for general fabrication and structural work.

AISI 1045 steel

A medium-carbon steel (about 0.45% carbon) that hardens readily, so it needs preheat and controlled cooling to avoid cracking.

Austenitic stainless behavior

300-series stainless has high thermal expansion and low thermal conductivity, so it distorts more and needs lower heat input and faster travel.

Aluminum oxide problem

Aluminum forms a refractory oxide that melts near 2050 C, far above the metal at about 660 C; AC GTAW or wire brushing removes it before welding.

Copper alloy welding

Copper conducts heat rapidly, so preheat and high current are needed for fusion; some alloys require fume controls during welding.

Cast iron repair

Cast iron is welded with nickel- or iron-based electrodes, low current, short beads, and preheat or peening to reduce shrinkage stress.

Hydrogen cracking sources

Moisture, rust, paint, and oil on the base metal or filler supply hydrogen that causes delayed cracking in high-strength steels.

Dissimilar metal filler choice

When joining dissimilar metals, the filler is chosen to match the lower-strength or more crack-sensitive side while maintaining compatibility.

Basic joint types

The five basic joints are butt, lap, tee, corner, and edge; the butt joint is most common for full-penetration pipe welds.

V-groove pipe angle

A typical pipe butt weld uses a V-groove with a 60-degree included angle, meaning a 30-degree bevel on each side.

Root opening and land

Root opening, root face (land), and bevel angle control root penetration and fusion; too much gap causes burn-through, too little causes lack of penetration.

Pipe schedule meaning

Pipe schedule indicates wall thickness for a given nominal diameter; thinner walls heat faster and need lower current and faster travel.

Tack weld requirements

Tacks must be full penetration and are consumed by the root pass; undersized tacks crack and oversized tacks cause lack of fusion.

Purge gas backing

An inert gas such as argon purges the pipe interior during root welding of stainless and titanium to prevent oxidation of the root.

Consumable insert root

A consumable insert placed in the root gap melts into the joint to give uniform root penetration and a smooth interior profile.

Fit-up tolerance effect

Excessive root gap causes burn-through, while too little gap or a heavy land causes lack of penetration at the root.