ASTM A217

Covers — martensitic stainless and alloy steel castings for pressure-containing parts at high temperature: grades WC1/WC4/WC5/WC6/WC9/WC11 (Cr-Mo), C5/C12/C12A (higher Cr), and CA15, used for valve bodies and turbine components.

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

• Carbon-steel castings → ASTM A216; austenitic stainless castings → ASTM A351.
• Forged alloy components → ASTM A182; alloy pipe → ASTM A335.
• Valve rating and wall thickness → ASME B16.34.

A217 grades pair with the matching A335 pipe and A182 forgings for creep and high-temperature service.

A217 sets minimum requirements for alloy castings:

• Chemistry — chrome-moly composition per grade (WC6 = 1¼Cr; WC9 = 2¼Cr; C12A = 9Cr-1Mo-V).
• Mechanical Properties — grade tensile/yield/elongation and hardness.
• Heat Treatment — normalize-and-temper (or as specified), with strict control and PWHT considerations for C12A/Grade 91.
• Testing — tension/hardness testing and NDE (RT/PT/MT) per referencing code; PMI verification.

ASTM A217 is the alloy and martensitic-stainless casting spec for valve bodies and pressure parts in high-temperature and creep service. WC6 and WC9 are the chrome-moly staples matching P11/P22 piping; C12A (Grade 91) serves supercritical power plants.

Correct heat treatment is decisive: like the forged and pipe equivalents, the chrome-moly grades develop their creep strength only through proper normalize-and-temper and controlled welding/PWHT. Valve ratings come from ASME B16.34.

Engineering Note: For C12A/Grade 91 castings, treat heat-treatment and PWHT records as critical quality documents — improper thermal history is a known cause of in-service creep cracking.