ASTM A403
Wrought austenitic stainless steel piping fittings
Covers wrought austenitic stainless steel piping fittings — elbows, tees, reducers, caps and stub ends — in seamless and welded construction, with grades named WP304, WP316L, WP904L and so on.
- Pipe fittings
- ASME SA-403
- 7 grades in stock range
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What to know before ordering to ASTM A403
The points that decide whether material to ASTM A403 is accepted at inspection.
- Class WP is made to ASME B16.9 / B16.11; Class CR is made to MSS SP-43.
- The suffix S, W or WX shows seamless, welded, or welded with full radiography.
- Dimensions come from ASME B16.9, not A403.
Grades and products we supply to ASTM A403
How ASTM A403 fits into an order
A purchase order line is only complete when it names the material standard, the dimensional standard and the inspection document. Miss one and the mill, the inspector and the buyer can each read the order differently.
Related standards
ASTM A403 — questions buyers ask
What does ASTM A403 cover?
Covers wrought austenitic stainless steel piping fittings — elbows, tees, reducers, caps and stub ends — in seamless and welded construction, with grades named WP304, WP316L, WP904L and so on.
Which grades do you supply to ASTM A403?
SS 904L, SS 304, SS 304L, SS 310 / 310S, SS 316 / 316L, SS 321, SS 347 — see the table on this page for the exact product and designation.
What is the difference between ASTM A403 and ASME SA-403?
ASME SA-403 is the ASME Boiler and Pressure Vessel Code (Section II) adoption of ASTM A403. The technical requirements are usually identical to a specific ASTM edition; pressure-equipment codes call for the ASME designation, and most mill certificates show both.
Do you supply certificates to this standard?
Yes. Material is supplied with mill test certificates to EN 10204 3.1 showing the standard, grade and heat number; 3.2 with third-party inspection on request.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026