ASTM A182

Covers — forged or rolled alloy-steel and stainless-steel flanges, forged fittings, valves, and parts for high-temperature service. Grades include chrome-moly (F1, F5, F9, F11, F22, F91), austenitic stainless (F304, F316, F321, F347), and duplex.

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

• Plain carbon-steel forgings → ASTM A105; low-temperature forgings → ASTM A350.
• Cast alloy/stainless components → ASTM A217 / A351.
• Finished-component dimensions and ratings → ASME B16.5 / B16.9 / B16.11.

One material spec, many grades — the F-designation must be stated to identify the alloy.

A182 sets minimum requirements per grade:

• Chemistry — composition limits specific to each F-grade (e.g., F22 = 2¼Cr-1Mo; F316 = 16Cr-12Ni-2Mo).
• Mechanical Properties — grade-specific tensile/yield/elongation and hardness.
• Heat Treatment — mandatory heat treatment per grade (anneal, normalize-and-temper, solution-anneal), with strict control for F91.
• Testing & Certification — tension/hardness testing, intergranular-corrosion testing where specified, and heat certification with PMI.

ASTM A182 is the master specification for forged alloy and stainless piping components in high-temperature service. It gathers many grades under one umbrella: chrome-moly grades for creep and elevated temperature, the advanced F91 grade for supercritical power plants, and austenitic F304/F316 for corrosion resistance.

Correct grade selection and the mandatory grade-specific heat treatment are what make an A182 component fit for service; PMI verification guards against mixed alloys. Component dimensions and ratings come from the B16 dimensional standards.

Engineering Note: For F91/Grade 91, control chemistry and post-weld heat treatment tightly — improper PWHT is a well-documented cause of premature creep failures in power-plant piping.