456A Cheat Sheet 2026

The 30 highest-yield 456A facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is 'kerf' in the context of oxyfuel cutting? → The width of material removed by the cutting process
2. On a weld symbol, on which side of the reference line is a weld symbol placed to indicate the 'arrow side' of the joint? → Below the reference line
3. In the electrode classification E7018, what does the '70' indicate? → Minimum tensile strength of 70,000 psi (480 MPa)
4. What is the primary cause of porosity in SMAW welds? → Contamination of the weld pool by gas (moisture, oil, or coating breakdown)
5. What does the 'E' in an electrode classification such as E7018 stand for? → Electrode
6. What is the significance of the 'H4' or 'H8' suffix on a low-hydrogen electrode designation such as E7018-H4? → The maximum diffusible hydrogen content in mL per 100g of deposited weld metal
7. What is the recommended inner-cone standoff distance when starting an oxyfuel cut on mild steel plate? → The inner cone approximately 3–6 mm (1/8–1/4 in) from the steel surface
8. What is the purpose of the 'crater fill' at the end of a SMAW weld bead? → To prevent crater cracks by filling the depression left when the arc is extinguished
9. What is the minimum recommended shielding gas flow rate for GMAW carbon steel welding (C25) to ensure adequate coverage? → 15–20 L/min (30–40 CFH)
10. What does a backing bar symbol look like on a welding symbol? → A rectangle placed on the opposite side of the reference line from the groove weld symbol
11. What does a circle at the intersection of the reference line and arrow indicate on a welding symbol? → The weld must go all around the joint (weld-all-around)
12. What does arc blow refer to in SMAW welding? → Deflection of the arc from its intended path due to magnetic fields
13. What is the recommended included angle for grinding a pointed tungsten tip for DCEN GTAW on steel? → 2.5× the electrode diameter length, ground longitudinally to produce a consistent tip
14. On a structural steel drawing for a connection, what does 'PL 25 × 200 × 600 A36' describe? → A plate, 25 mm thick × 200 mm wide × 600 mm long, made from ASTM A36 steel
15. What is the maximum allowable working pressure for acetylene in Canada? → 103 kPa (15 psi)
16. A welder qualified in the 2G position (pipe horizontal, axis vertical) under CSA W47.1 is also qualified to weld in which positions? → 1G and 2G
17. What is the 'autogenous' GTAW technique? → Welding without filler metal addition, relying solely on fusion of the base metal edges
18. What filler metal would be used for GTAW welding of 304 stainless steel? → ER308L
19. What is the minimum lens shade number recommended for SMAW welding at 150–200 amperes, per CSA Z94.3? → Shade 10
20. What is the Vickers Hardness (HV) limit typically specified for the HAZ in sour service (H2S) environments per NACE MR0175/ISO 15156? → 250 HV maximum
21. What type of polarity is typically used for self-shielded FCAW? → DCEN (DC Electrode Negative / Straight Polarity) for most self-shielded wires
22. What does the dimension placed to the left of a fillet weld symbol represent? → The leg size of the fillet weld
23. When welding with E7018 electrodes, what defect is most likely if the electrodes have absorbed moisture? → Hydrogen-induced cracking (underbead cracking)
24. What does the 'hierarchy of controls' for welding hazards specify, in order from most to least preferred? → Elimination → Substitution → Engineering controls → Administrative controls → PPE
25. What does AWS D1.1 (or CSA W59 equivalent) specify as the maximum allowable face reinforcement for a complete joint penetration groove weld? → 3 mm (1/8 in) maximum reinforcement above the base metal surface
26. What type of tungsten electrode is recommended for AC GTAW welding of aluminum? → Pure tungsten (EWP) or zirconiated tungsten (EWZr)
27. What is the amperage range typically used for GTAW of 3 mm (1/8-inch) stainless steel with a 2.4 mm tungsten electrode? → 70–110 A DCEN
28. What is the 'heat input' formula used in GTAW welding procedure qualification? → HI = (Amps × Volts × 60) / (Travel Speed in mm/min) = J/mm
29. What does a double-sided V-groove symbol (X-groove) indicate on a drawing? → Full penetration groove weld to be made from both sides of the joint
30. What is 'overlap' (cold lap) as a weld discontinuity in SMAW? → Weld metal that extends beyond the weld toe onto the base metal without fusing to it