CWE flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Welding filter shade selection
- Filter shade number depends on process and current: higher amperage needs a darker shade. Too light a shade risks arc eye from UV/IR; too dark reduces visibility and may cause unsafe posture.
- Fire watch duration
- A fire watch must remain at least 30 minutes after welding stops, because hot slag and concealed smoldering material can ignite well after the arc is extinguished.
- Open-circuit voltage hazard
- OCV is the voltage present at the electrode before the arc starts. Higher OCV increases shock severity, especially with wet gloves, damp clothing, or standing on grounded steel.
- Confined space welding control
- Confined-space welding requires atmospheric testing for oxygen and flammable or toxic gas before entry and continuously during work, plus ventilation and a standby attendant outside.
- Tensile test outputs
- A tensile test reports yield strength, ultimate tensile strength, percent elongation, and percent reduction of area. These show both strength and ductility of the welded joint.
- Guided bend test purpose
- Bend tests evaluate ductility and fusion at the weld face and root. After bending, the specimen is examined for discontinuities exceeding the specified size limit.
- Charpy impact test
- A Charpy V-notch test measures absorbed energy in joules at a stated temperature. Ferritic steels lose toughness as temperature falls, so the temperature must always accompany the result.
- Heat-affected zone
- The HAZ is base metal that was not melted but had its microstructure altered by welding heat. It often has the highest hardness and lowest toughness in the joint.
- Carbon equivalent formula
- CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15. Higher CE means greater hardenability and cold-cracking risk, so preheat and hydrogen control increase.
- Welding symbol reference line
- The reference line carries the weld symbols. Information above the line applies to the arrow side; information below applies to the other side of the joint.
- Fillet weld size position
- On a welding symbol, the fillet size is placed to the left of the fillet symbol and the length to the right. A pitch value follows the length for intermittent welds.
- Penetrant testing limitation
- Penetrant testing finds surface-breaking discontinuities only. It requires a clean, non-porous surface, and it cannot detect internal flaws or defects covered by weld metal.
- Magnetic particle testing scope
- Magnetic particle testing applies only to ferromagnetic materials and detects surface and near-surface discontinuities. It is ineffective on austenitic stainless steel and aluminum.
- Radiographic testing sensitivity
- Radiography detects internal discontinuities as density or thickness changes. Planar defects oriented parallel to the beam may be missed, so orientation of the source matters.
- Ultrasonic testing advantage
- Ultrasonic testing detects internal planar discontinuities such as lack of fusion and cracks, and it can measure their depth. It requires a trained operator and a suitable surface finish.
- WPS versus PQR
- The PQR documents the test coupon and results that qualified a procedure. The WPS is written from that qualification and instructs production welding. They are separate documents with separate purposes.
- Welder performance qualification
- A welder is qualified separately from the procedure, by producing a test weld to a qualified WPS that passes the required tests. A qualified WPS does not qualify a welder.
- Essential variable change
- A change outside the qualified range of an essential variable, such as process, filler classification, base-metal group, thickness, or preheat, requires requalification of the procedure before production use.
- Non-essential variable
- A non-essential variable change, such as a travel angle or a minor technique adjustment, does not require requalification. It is handled by revising the WPS, not by retesting.
- Preheat measurement location
- Preheat is measured at least 75 mm (3 in) from the joint on both sides before welding. Contact thermometers, temperature sticks, or thermocouples provide the verification.
- Interpass temperature limit
- Interpass temperature is the maximum allowed temperature between passes. Exceeding it can reduce toughness in the HAZ and weld metal, so it is a controlled variable in the WPS.
- Fillet weld throat formula
- For an equal-leg fillet at 90 degrees, theoretical throat equals 0.707 times the leg length. Throat is the governing dimension for fillet weld strength calculations.
- Fillet weld gauge use
- A fillet weld gauge checks leg length and throat against the specified size. The correct gauge leaf must contact both the base metal and the weld face without gaps.
- Undercut measurement tool
- A bridge cam gauge or pit gauge measures undercut depth and weld cap height. Measured values are compared with the acceptance criteria for the specific joint and code.
- V-WAC gauge purpose
- The V-WAC gauge measures weld cap height, undercut depth, and pit depth. It is placed across the weld so the reference edges rest on the base metal.
- Hi-lo misalignment gauge
- A hi-lo gauge measures internal mismatch between the two pipe or plate surfaces at the joint. Excessive mismatch concentrates stress and may exceed the allowable offset.
- Root gap and root face
- Root gap is the separation between joint faces at the root; root face is the un-beveled land. Both control penetration and must match the WPS fit-up requirements.
- Heat input formula
- Heat input in kJ/mm equals voltage times current times 60, divided by travel speed in mm/min, times 1000. It must stay within the WPS range to protect toughness.
- Backstep welding technique
- Backstep welding deposits short beads in the direction opposite to the overall progression. It spreads heat and reduces distortion and cracking in restrained joints.
- Balanced welding sequence
- A balanced sequence alternates welding on opposite sides of the joint or about the neutral axis. It balances shrinkage forces and limits angular distortion.
- NDT before PWHT
- Required NDT is normally completed before post-weld heat treatment and before coating. Defects found after PWHT may require reheat treatment following repair.
- Weld traceability records
- Records should link base-metal heat numbers, filler lot numbers, the WPS and PQR used, and the welder identification. This supports later inspection and quality audits.