AWS AWS D1.1 Structural Welding Code 2 — Questions and Answers
Question 1: AWS D1.1 requires that welding procedure specifications (WPS) include which essential variables?
- Welder's name and certification number
- Process, joint design, base metal, filler metal, position, preheat, and PWHT (Correct answer)
- The Engineer's signature only
- Only the amperage and voltage settings
Correct answer: Process, joint design, base metal, filler metal, position, preheat, and PWHT
A WPS under AWS D1.1 must document all essential variables: welding process, joint design/geometry, base metal group, filler metal classification, welding position, preheat/interpass temperature, and post-weld heat treatment if applicable.
AWS D1.1 Clause 4.4 defines WPS content requirements. Essential variables (whose change requires re-qualification) include: welding process; joint design; base metal group; filler metal AWS classification; position; electrical characteristics (polarity, current type); preheat/interpass temperature; shielding gas composition; PWHT; and technique. Non-essential variables may be changed within a WPS without re-qualification but must be documented. The WPS is the roadmap the welder follows; the PQR (procedure qualification record) provides test data supporting the WPS.
Question 2: Under AWS D1.1, what is the minimum preheat temperature for ASTM A572 Grade 50 steel, 1.5 inches thick, welded with SMAW using E7018?
- No preheat required
- 50°F
- 150°F (Correct answer)
- 225°F
Correct answer: 150°F
AWS D1.1 Table 4.5 requires 150°F (65°C) minimum preheat for A572 Grade 50 (Group II steel) at thicknesses over 1.5 inches with low-hydrogen electrodes.
AWS D1.1 Table 4.5 organizes structural steels into Groups I–IV by carbon equivalent and composition. ASTM A572 Grade 50 falls in Group II. Preheat requirements increase with material thickness and carbon equivalent. For Group II steel: low-hydrogen electrodes (E7018), thickness over 1.5 inches requires 150°F minimum preheat. Non-low-hydrogen electrodes would require 225°F at this thickness. Interpass temperature minimum equals preheat; maximum interpass is typically 450°F for carbon steel unless otherwise specified by the Engineer.
Question 3: According to AWS D1.1, the minimum fillet weld size for a base metal thickness of 3/4 inch is:
- 3/16 inch
- 1/4 inch (Correct answer)
- 5/16 inch
- 3/8 inch
Correct answer: 1/4 inch
AWS D1.1 Table 6.1 specifies a minimum fillet weld size of 1/4 inch for base metal thicknesses from 1/2 inch through 3/4 inch.
AWS D1.1 Table 6.1 sets minimum fillet weld sizes based on the thicker part joined to ensure adequate heat input and prevent cracking from rapid cooling of the weld relative to the base metal: ≤1/4 inch thick = 1/8 inch min; >1/4 to 1/2 inch = 3/16 inch min; >1/2 to 3/4 inch = 1/4 inch min; >3/4 inch = 5/16 inch min. For 3/4-inch (exactly at boundary) use the larger category requiring 1/4 inch. These minimums ensure the weld has sufficient thermal mass to prevent hydrogen cracking in restrained joints.
Question 4: Porosity acceptance criteria under AWS D1.1 for statically loaded non-tubular connections limit visible porosity to:
- No porosity is permitted on any weld
- Maximum 3/8-inch diameter individual pores and total area not exceeding 3/8 inch in any linear inch (Correct answer)
- Any size porosity is acceptable if the weld meets size requirements
- Maximum 1/16-inch pores only
Correct answer: Maximum 3/8-inch diameter individual pores and total area not exceeding 3/8 inch in any linear inch
D1.1 Clause 6.9.2 limits visible porosity for statically loaded structures to maximum 3/8-inch diameter for any individual pore and aggregate porosity not exceeding 3/8 square inch in any 1-inch length of weld.
AWS D1.1 visual acceptance criteria for porosity differ by loading type. For statically loaded structures (Clause 6.9.2): individual pores ≤3/8 inch diameter; sum of porosity diameters ≤3/8 inch per linear inch. For cyclically loaded structures (Clause 6.10.2), more stringent limits apply — typically ≤1/16-inch diameter for welds transverse to tension. RT and UT inspection have separate subsurface porosity criteria in Clauses 6.12 and 6.13 respectively. Inspectors must reference the correct clause for the structural application.
Question 5: Under AWS D1.1, a welder who passes a groove weld qualification test in the 3G position is also qualified to weld in which positions?
- 3G only — each position requires separate qualification
- 1G and 2G only
- 1F, 2F, 3F, 1G, and 2G (flat, horizontal, and all fillet weld positions) (Correct answer)
- All positions including 4G and 6G
Correct answer: 1F, 2F, 3F, 1G, and 2G (flat, horizontal, and all fillet weld positions)
Per AWS D1.1 Table 4.12, passing a 3G (vertical groove) qualification qualifies the welder for flat (1G/1F), horizontal (2G/2F), vertical (3G/3F) groove and fillet weld positions.
AWS D1.1 Table 4.12 defines position qualification ranges. A 3G (vertical groove) test qualifies the welder for: 1G (flat groove), 2G (horizontal groove), 3G (vertical groove), 1F (flat fillet), 2F (horizontal fillet), and 3F (vertical fillet). It does not qualify for 4G (overhead groove) or 4F (overhead fillet) — those require additional testing. The 4G test adds overhead qualification. Full position qualification (all positions) requires testing in 3G and 4G, or the 6G (45-degree pipe) test which qualifies for all positions on pipe and structural applications.
Question 6: What action is required when a weld is found to contain a crack under AWS D1.1?
- Grind the crack flush and reweld over it without removal
- Stop welding, notify the engineer, completely remove the crack, and repair per approved procedure (Correct answer)
- Accept the crack if it is under 1/4 inch in length
- Grind the crack to blend it and continue welding
Correct answer: Stop welding, notify the engineer, completely remove the crack, and repair per approved procedure
AWS D1.1 categorically prohibits cracks in welds (Clause 6.9.1). Any crack found requires work stoppage, notification of the responsible engineer, complete crack removal (verified by NDE), and repair using an approved WPS.
AWS D1.1 Clause 6.9.1 states: 'Cracks are unacceptable.' Unlike some other discontinuities that have size-based acceptance criteria, cracks of any size, in any location, are rejectable under D1.1 visual inspection. Corrective action: stop work; notify the Engineer; completely excavate the crack by grinding, gouging, or cutting (confirmed crack-free by MT or PT); repair with an approved WPS; and re-inspect. Grinding over a crack without removal is strictly prohibited as it conceals the defect. Weld cracks often indicate a procedural issue (preheat, hydrogen, restraint) that must be addressed before repair welding.
AWS AWS D1.1 Structural Welding Code 2
AWS D1.1 requires that welding procedure specifications (WPS) include which essential variables?