CW Certified Welder flashcards

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

SMAW electrode polarity

E6010 and E6011 cellulosic electrodes usually run on direct current electrode positive (DCEP), while many low-hydrogen basic electrodes run on DCEP or alternating current.

GMAW spray transfer

Spray transfer uses high current and argon-rich shielding to produce a fine axial droplet stream; it gives deep penetration and high deposition but is not suitable for thin sheet or vertical work.

FCAW self-shielded

Self-shielded flux-cored arc welding needs no external shielding gas; the flux core generates shielding, making it tolerant of wind and useful for field erection.

GTAW AC output

Alternating current in gas tungsten arc welding alternates cleaning and penetration half-cycles; it is used mainly for aluminum and magnesium to break up surface oxide.

Essential variable

An essential variable is a welding parameter, such as process, filler classification, shielding gas, polarity, or transfer mode, that must be requalified when changed beyond code limits.

Short-circuit transfer

Short-circuiting GMAW uses low voltage and current; the wire contacts the puddle and extinguishes the arc repeatedly, producing a small, fast-freezing puddle for thin material and out-of-position work.

Low-hydrogen electrode storage

Basic low-hydrogen electrodes absorb moisture and must be held in heated storage or baked per manufacturer instructions; damp electrodes can cause hydrogen cracking in high-strength steel.

Process selection rule

Choose SMAW or self-shielded FCAW for windy outdoor work, GTAW for thin high-quality joints, and GMAW spray for high-deposition flat work on thick steel.

Flat position

In the flat position the weld is made from the top side with the weld face approximately horizontal; molten metal is supported by the joint and gravity assists deposition.

Horizontal position

In the horizontal position the weld axis is horizontal and the weld face is vertical; the molten puddle tends to sag downward, so heat input and travel technique must be controlled.

Vertical uphill welding

Vertical uphill welding progresses from bottom to top, using a short arc and controlled weave; it gives better penetration and is often required for code qualification.

Overhead position

In the overhead position welding is performed from below the joint with the weld face downward; lower current and fast-freezing electrodes help control the puddle against gravity.

6G pipe position

The 6G test has a pipe fixed at 45 degrees and is not rotated; it is the most demanding pipe position and commonly qualifies all pipe positions when code allows.

5G pipe position

The 5G test uses a horizontal fixed pipe that is not rotated; the welder must weld flat, vertical, and overhead sections around the circumference.

Position qualification rule

A welder qualified in a more difficult position does not automatically qualify for every position unless the applicable code states it; position changes are essential variables.

Downhill vertical welding

Downhill vertical welding travels from top to bottom and produces less penetration; it is generally limited to thinner material or specific electrodes and is a separate qualification variable.

Pipe diameter essential variable

Pipe diameter is an essential variable in most welder qualification codes; a coupon from one diameter range may not qualify another without meeting specific code grouping rules.

Plate-to-pipe qualification

A plate test does not automatically qualify a welder for pipe; pipe tests are more restrictive because of curvature and fixed-position welding, though some codes allow limited plate qualification.

Wall thickness qualification

Test coupon wall thickness sets the qualified thickness range; thicker coupons usually qualify thinner material, while thinner coupons rarely qualify thicker material without code approval.

Base metal grouping

Base metals are grouped by strength, composition, and weldability; changing from carbon steel to stainless steel or aluminum generally requires a separate procedure and welder qualification.

Small-diameter pipe

Small-diameter pipe is commonly NPS 2 or less; its tight curvature forces more torch or electrode angle changes and often requires 5G or 6G testing.

Large-diameter pipe

Large-diameter pipe allows longer welds before repositioning; diameter and wall thickness still remain essential variables for procedure and performance qualification.

Backing as essential variable

Using or removing backing changes root support and heat flow; in many codes backing is an essential variable that requires requalification when changed.

Aluminum oxide removal

Aluminum forms a refractory oxide that must be removed by stainless wire brushing or chemical cleaning and is broken up during GTAW by alternating current.

Cracks in test weld

Cracks are planar discontinuities and are generally rejectable in a welder qualification test regardless of length or location; the weldment must be repaired or replaced.

Undercut acceptance

Undercut is a groove melted into the base metal at the weld toe; acceptance depends on depth and length limits, and excessive undercut reduces the effective throat.

Porosity acceptance

Porosity is gas trapped in the weld; acceptance usually depends on pore size, distribution, and total area or count per length of weld.

Bend test purpose

A bend test evaluates ductility and fusion at the root or face; the specimen is bent around a specified radius and inspected for cracks or tears exceeding code limits.

Tensile test requirement

A tensile specimen must reach at least the minimum specified tensile strength of the base metal; failure below that value or in the weld may fail the test.

Visual inspection first

Visual inspection is performed before mechanical testing; the test weld must be free of surface cracks, excessive reinforcement, and other code-rejectable surface discontinuities.

Reinforcement limit

Weld reinforcement is the metal above the base-metal surface; excessive cap height concentrates stress and may be rejectable under code acceptance criteria.

Discontinuity versus defect

A discontinuity is any interruption in the weld's uniformity; it becomes a defect only when it exceeds the acceptance limit in the applicable code.