Technical Bulletin | PQR vs. WPS: How We Make Every Weld on Your Stainless-Steel Vessel Traceable and Reliable
(Information-only sharing — no downloads required)
Prepared by YITENG PV WELDING TEAM.
––– Key points distilled from industry sources, rewritten for our customers –––
1. One diagram Two roles
• PQR (Procedure Qualification Record) = “the exam”
- A test coupon is welded and then subjected to tensile, bend, impact and macro-etch tests.
- Results are recorded, locked, and cannot be altered.
• WPS (Welding Procedure Specification) = “the instruction manual”
– Derived directly from the successful PQR.
– Gives welders exact ranges for amperage, voltage, travel speed, pre-heat, inter-pass temperature, filler metal, shielding gas, etc.
2. Why the “exam” comes first
• Code-driven: ASME IX, PED 2014/68/EU and GB/T 150 all require a qualified PQR before any production WPS is issued.
• Risk control: If any mechanical test fails, the entire parameter set is rejected and retested—no exceptions.
• Lifetime traceability: The PQR number is stamped on the product data package and stays valid indefinitely.
3. What you’ll find in our WPS
• Qualified thickness range (e.g., 3 mm – 12 mm).
• Allowed welding positions (1G, 2G, 3G, 4G, 6G).
• Heat-input limits calculated from the PQR’s actual values.
• Reference back to the PQR number and revision—so you can audit the original test data at any time.
4. How we keep production identical to the test
• Dual check: Welding engineer + QC inspector both sign off before a WPS is released to the shop floor.
• Live logging: Critical parameters are recorded for every weld; RT/UT spot checks ensure deviation < 3 %.
• Re-qualification: Any change beyond the PQR’s essential variables triggers a new PQR and a new WPS.
5. FAQ from our customers
Q1: We need both 8 mm and 12 mm thicknesses—one PQR or two
A: If our existing PQR covers the range 8–12 mm, one is enough. Otherwise, we run an additional coupon.
Q2: Can we use another fabricator’s PQR?
A: Only if material grade, joint design, consumable and gas match 100 % and written authorization is provided.
Q3: How fast can you issue a WPS?
A: For common stainless grades (304L, 316L, 2205) we hold 60+ pre-qualified PQRs—WPS ready within 24 h. New material trials take 7–10 days.
At YITENG PV, every weld is “examined before executed.” If you’d like the PQR/WPS numbers for your current order—or just want to talk about heat-input limits—drop us a line.
Email: yeekai@yitengrq.com
Tel/WhatsApp: +86-186-5249-2007
For 15 years, YITENG PV have focused on stainless-steel pressure vessels and modular systems. We hold ASME “U” stamps, NB registration, PED 2014/68/EU approval, and ISO certification. Every weld—from PQR and WPS through final RT/UT—is fully traceable, giving you total confidence in every product we manufactured.
