This WPS covers SMAW fillet welds on 3/8" 304L stainless steel per AWS D1.6 Structural Welding Code — Stainless Steel. The procedure qualifies all positions with E308L electrodes and includes the critical stainless-specific details that carbon steel procedures don't address — interpass temperature limits, heat input control, and contamination prevention. IronKit generated this for a stainless fabrication shop that builds food processing equipment and pharmaceutical frames. The shop said the maximum interpass temperature and stainless-only tooling note were the two details they'd been inconsistently enforcing before having a formal WPS.
Frequently Asked Questions
Why is interpass temperature limited to 350°F for stainless?
Austenitic stainless steels (300-series) are susceptible to sensitization — chromium carbide precipitation at grain boundaries — when held between 800–1,500°F. Limiting interpass to 350°F keeps the HAZ from accumulating excessive heat. Sensitized stainless loses its corrosion resistance.
What does "L-grade" mean in E308L?
L stands for low carbon (max 0.03% C vs. 0.08% for standard 308). Low carbon reduces the risk of sensitization during welding. For most structural and food-grade stainless work, L-grade filler is standard practice and often required by code.
Why can't I use carbon steel brushes on stainless?
Carbon steel particles embedded in the stainless surface will rust and contaminate the corrosion-resistant oxide layer. All cleaning tools, grinding discs, clamps, and fixtures that contact the stainless must be stainless steel or non-contaminating materials. This is a basic shop requirement for any stainless fabrication.
Does IronKit include heat input limits?
Yes. IronKit calculates maximum heat input per inch based on the material grade and thickness. For 304L, the limit prevents sensitization and is displayed in the electrical parameters section of the WPS.