CWI flashcards

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

SMAW electrode E7018

Low-hydrogen, iron-powder covered electrode rated 70,000 psi minimum tensile strength, usable in all positions on AC or DC; the coating must be kept dry to prevent hydrogen-assisted cracking.

E6010 electrode characteristics

Cellulosic sodium-coated electrode producing a forceful arc and deep penetration; operates on DC electrode positive only and is widely used for root passes and pipe welding.

GMAW spray transfer

Requires high current and argon-rich shielding gas to produce a fine axial spray of droplets, giving high deposition and deep penetration; generally limited to flat and horizontal positions.

GTAW AC for aluminum

Alternating current alternates a cleaning half-cycle that breaks up the aluminum oxide film with a penetration half-cycle; used for aluminum and magnesium because the oxide must be removed.

Heat input formula

Heat input in joules per inch equals 60 multiplied by the arc voltage multiplied by the amperage, divided by the travel speed expressed in inches per minute.

Carbon equivalent purpose

An empirical number calculated from steel chemistry that estimates hardenability and weldability; higher values signal a greater need for preheat and hydrogen control.

FCAW self-shielded

Uses a flux-cored wire whose core supplies shielding and slag, so no external gas is needed; the process tolerates wind and is therefore common on outdoor field work.

SAW process features

Submerged arc welding buries the arc under a blanket of granular flux with a continuously fed wire, producing high deposition and deep penetration in flat or horizontal positions.

Fillet weld throat

The shortest distance from the joint root to the face of the fillet weld; for an equal-legged 45 degree fillet, the throat equals 0.707 times the leg.

Common groove weld types

Square, single-V, double-V, single-bevel, single-U and single-J grooves; the shape is chosen based on material thickness, joint access, and cost.

Welding position 3G

A groove weld made with the plates vertical and the weld axis vertical, progressing upward or downward; it is a standard skill test for all-position welders.

Visual inspection illumination

AWS D1.1 requires a minimum of 1000 lux, roughly 100 foot-candles, at the surface being examined, along with adequate access and unobstructed line of sight.

Penetrant testing limitation

Detects only discontinuities that are open to the surface of nonporous materials; subsurface flaws cannot be found, and the surface must be clean and dry.

Magnetic particle testing scope

Applies only to ferromagnetic materials and reveals surface and near-surface discontinuities; alternating current favors surface sensitivity while direct current reaches deeper.

Ultrasonic testing principle

High-frequency sound is transmitted into the part and echoes from reflectors are displayed; the method is best at planar flaws oriented perpendicular to the beam.

Radiographic testing principle

Radiation passes through the part and exposes film or a detector; differences in density reveal internal volumetric flaws, while planar flaws parallel to the beam may be missed.

Hi-lo gauge use

Measures internal misalignment of abutting pipe or plate surfaces; excessive high-low misalignment promotes lack of fusion and incomplete penetration at the root.

Fillet weld gauge

A gauge used to measure the leg size, and on some designs the throat, of a fillet weld so the measured size can be compared to the specified size.

Undercut gauge

A gauge with pointed or stepped blades that measures the depth of undercut at the weld toe so the reading can be compared against the code limit.

NDE personnel qualification

ASNT SNT-TC-1A is a recommended practice for employer-written qualification programs; Levels I, II and III define increasing responsibility, and the employer issues certification.

Discontinuity versus defect

A discontinuity is any interruption in the material; it is called a defect only after it exceeds the acceptance criteria of the applicable code.

Weld inspection stages

Inspection occurs before welding (materials, fit-up, procedure, qualifications), during welding (root pass, interpass), and after welding (final visual examination followed by NDE).

AWS D1.1 scope

Structural Welding Code - Steel; it covers design, procedure and personnel qualification, fabrication, and inspection of welded steel structures and is the most common CWI reference.

Prequalified WPS

A welding procedure that uses only joints and essential variables listed in AWS D1.1 Clause 3; it needs no mechanical testing but must still be written and followed.

WPS essential variable

A condition such as welding process, position, thickness range, filler metal classification, preheat, or current type whose change requires requalification of the welding procedure specification.

D1.1 butt weld reinforcement

Weld reinforcement on a butt joint shall not exceed 1/8 in (3 mm); reinforcement within that limit does not have to be removed.

D1.1 undercut limit

Undercut shall not exceed 1/32 in (1 mm) in depth; deeper undercut up to 1/16 in is permitted only in limited cumulative lengths within any 12 in.

Minimum fillet weld size

Based on thinner part thickness: up to 1/4 in requires 1/8 in; over 1/4 to 1/2 in requires 3/16 in; over 1/2 to 3/4 in requires 1/4 in.

Minimum fillet weld length

A fillet weld must be at least four times its nominal size in length; if it is shorter, the effective size is taken as the length divided by four.

ASME Section IX

Covers qualification of welding procedures, welders, and operators for ASME pressure equipment through the WPS, the PQR, and performance qualification; it is not a construction code.

API 1104 scope

Standard for welding pipelines and related facilities; it sets requirements for procedure and welder qualification and for acceptance of girth welds in transmission pipelines.

Inspector authority source

An inspector's authority comes from the contract documents and the referenced code, so each acceptance or rejection decision should cite a specific code clause or drawing requirement.