ASTM A351

Covers — austenitic and duplex stainless steel castings for pressure-containing parts: CF8 (304), CF8M (316), CF3/CF3M (304L/316L), CN7M, and others, used for valve bodies, pump casings, and fittings.

Does NOT cover (exclusions) — the following are governed elsewhere:

• Carbon-steel castings → ASTM A216; alloy/martensitic castings → ASTM A217.
• Wrought (forged) stainless components → ASTM A182.
• Valve pressure-temperature rating → ASME B16.34.

CF8M is the cast form of 316 stainless — do not treat cast and wrought grades as identical in welding and toughness.

A351 sets minimum requirements for stainless castings:

• Chemistry — austenitic/duplex grade composition (CF8M ≈ 316), with controlled ferrite for weldable grades.
• Mechanical Properties — grade tensile/yield/elongation.
• Heat Treatment — mandatory solution annealing and quench to restore corrosion resistance.
• Testing — tension testing, intergranular-corrosion testing where specified, and NDE (RT/PT) per referencing code.

ASTM A351 is the standard for austenitic and duplex stainless steel castings used in valve bodies and other pressure parts. CF8M is the cast counterpart of 316, CF8 of 304, and CF3M of 316L — the everyday cast grades for corrosive process service.

Mandatory solution annealing restores the corrosion resistance disturbed by casting. Unlike wrought stainless, cast grades carry some delta-ferrite, which aids weldability but must be considered for low-temperature and specialized service.

Engineering Note: For as-cast, as-welded corrosive duty, specify a low-carbon grade (CF3M) to avoid sensitization — the same 304L/316L logic that applies to wrought stainless.