SPED Pipe Fabrication & Welding Standards 2 — Questions and Answers
Question 1: According to ASME B31.3, what is the minimum preheat temperature required for P-No. 1 carbon steel pipe with a wall thickness exceeding 1 inch?
- 50°F (10°C)
- 175°F (79°C) (Correct answer)
- 250°F (121°C)
- 300°F (149°C)
Correct answer: 175°F (79°C)
ASME B31.3 Table 331.1.1 requires a minimum preheat of 175°F for P-No. 1 steels when the nominal wall thickness exceeds 1 inch.
Question 2: Which NDE method is most effective for detecting subsurface volumetric defects such as porosity and inclusions in a weld?
- Magnetic particle testing (MT)
- Liquid penetrant testing (PT)
- Radiographic testing (RT) (Correct answer)
- Visual testing (VT)
Correct answer: Radiographic testing (RT)
Radiographic testing uses X-ray or gamma-ray radiation to reveal volumetric internal defects like porosity and slag inclusions throughout the weld cross-section.
Question 3: In pipe fabrication, what does the term 'fit-up' refer to?
- The process of heat-treating pipe joints after welding
- The alignment and gap preparation of pipe ends before welding (Correct answer)
- The final inspection of a completed weld joint
- The selection of filler metal for a given base material
Correct answer: The alignment and gap preparation of pipe ends before welding
Fit-up is the preparation step where pipe ends are aligned, gapped, and tacked in position to ensure proper joint geometry before the root pass is deposited.
Question 4: What is the primary purpose of a Procedure Qualification Record (PQR) in welding?
- To document the welder's personal certifications and training history
- To record the actual test variables used to qualify a Welding Procedure Specification (Correct answer)
- To list all approved filler metals for a given project
- To track heat numbers for traceability of pipe materials
Correct answer: To record the actual test variables used to qualify a Welding Procedure Specification
A PQR is a record of the welding data and test results from the coupon tests used to qualify a WPS, as required by ASME Section IX.
Question 5: Under ASME B16.25, which end preparation is considered a standard butt-welding end for pipe nominal sizes 2½ inches and larger with wall thicknesses up to 0.88 inches?
- Square cut end
- Single-V groove at 37.5° (Correct answer)
- Double-V groove at 45°
- J-groove preparation
Correct answer: Single-V groove at 37.5°
ASME B16.25 specifies a single-V bevel at 37.5° (±2.5°) from the pipe axis as the standard butt-welding end prep for the specified size and thickness range.
Question 6: Which ASME Section IX P-Number group includes austenitic stainless steels such as Type 304 and 316?
- P-No. 1
- P-No. 6
- P-No. 8 (Correct answer)
- P-No. 10
Correct answer: P-No. 8
ASME Section IX assigns P-No. 8 to austenitic stainless steels, including commonly used grades 304, 304L, 316, and 316L.
Question 7: In SMAW (Shielded Metal Arc Welding) of pipe, what is the purpose of the 'stringer bead' technique versus the 'weave bead' technique?
- Stringer beads produce wider passes with more heat input than weave beads
- Stringer beads are narrow passes with lower heat input; weave beads are wider with higher heat input (Correct answer)
- Stringer beads are used only for root passes while weave beads are prohibited in all positions
- Stringer beads require higher amperage settings than weave beads of equal width
Correct answer: Stringer beads are narrow passes with lower heat input; weave beads are wider with higher heat input
Stringer beads travel in a straight line producing narrow, lower-heat-input passes ideal for heat-sensitive materials, while weave beads oscillate laterally to cover more width but introduce more heat.
SPED Pipe Fabrication & Welding Standards 2
According to ASME B31.3, what is the minimum preheat temperature required for P-No. 1 carbon steel pipe with a wall thickness exceeding 1 inch?