Temperature control · Clause 5 and Clause 6
How do you set interpass temperature in an AWS D1.1 WPS?
A WPS needs a temperature rule that can be applied before each pass. The minimum is linked to the applicable preheat or qualified minimum. A maximum is a separate limit when required by the material, CVN qualification or project. There is no universal maximum interpass number for every steel and process.
Use the right source for each route
| WPS route | Minimum interpass evidence | Maximum interpass question |
|---|---|---|
| Clause 5 prequalified | Check each material's Table 5.11 category for the actual process/electrode condition and the thickest part at the weld; use the governing minimum with Clause 7.6 and project conditions. | Check material-specific requirements, the project and any toughness condition. Do not insert a generic 250°C ceiling. |
| Existing PQR under Clause 6 | Under 6.8.4, establish the qualified minimum preheat; minimum interpass equals that qualified minimum. Keep the coupon's actual temperatures and chosen WPS minimum traceable. | Where CVN is required, or the material requires it, list the maximum in the WPS and review Table 6.8 supplemental variables and any producer limit. |
For a PQR coupon, if the weld cools below the qualified minimum before a further pass, reheat to at least that minimum before welding resumes. A blank coupon temperature log cannot be treated as a measured minimum. The weld parameter record separates actual pass observations from proposed WPS settings.
Bounded example: a minimum is not a maximum
Suppose the supported Table 5.11 result for a specific two-member, 25 mm, GMAW joint is 65°C (see the two-member preheat example). The WPS review uses that as a minimum temperature starting point under the stated assumptions and any higher project requirement. It does not infer a maximum of 250°C or any other value. If a contract requires CVN, a producer limits a Q&T steel, or the project specifies a maximum, obtain that evidence and check the route-specific qualification implications before setting the upper bound.
The required measurement is the temperature in the prescribed weld region before the next pass, not merely the heating-device setting. Clause 7.6 controls the heated region and pre-pass checks. Record the measurement point, instrument/method, pass, time and actual reading when a production log is required.
Review a proposed change
- Identify whether the WPS is prequalified or PQR-based and the project's edition, steel condition, process and CVN requirement.
- Trace the proposed minimum to the governing material and thickness calculation or the qualification-test method. Do not use a different steel's category.
- Ask whether a maximum is required by material producer, CVN qualification or contract, and record its exact source and unit system.
- For a PQR-based WPS, compare the change with the applicable Table 6.6 variables and, where CVN applies, Table 6.8. A table trigger is a requalification check, not an automatic operating range.
- Write the field instruction and pre-pass measurement point so welders can actually apply the limit.
Code basis and scope
Basis: AWS D1.1/D1.1M:2025 base edition plus registered July 28, 2026 base-edition errata; AMD1 is excluded. Relevant provisions include Table 5.11 and Clause 5.7 for the prequalified temperature route, Clause 6.8.4 and Table 6.8 for qualification and CVN-related limits, and Clause 7.6 for production temperature control. Q&T steel and material-specific heat limits require the steel producer's applicable recommendations. The contract edition and project documents govern.
This guide does not set a temperature for an unidentified steel, infer a maximum from an electrode name, or validate an actual PQR. Use the underlying records for those decisions.
Provide both material records, the temperature requirement, process and any PQR/CVN evidence.