What Is ASTM A182?
Grades at a Glance
ASTM A182 encompasses dozens of grades across three material families. The table below covers the most frequently specified grades.
| Grade | Alloy Type | Wrought Equiv. | Cast Equiv. | Max Temp | Primary Use |
|---|---|---|---|---|---|
| F1 | C-1/2Mo | A335 P1 | A217 WC1 | 455°C | Moderate high-temp |
| F11 | 1-1/4Cr-1/2Mo | A335 P11 | A217 WC6 | 565°C | Refinery, power |
| F22 | 2-1/4Cr-1Mo | A335 P22 | A217 WC9 | 595°C | Hydroprocessing |
| F5 | 5Cr-1/2Mo | A335 P5 | A217 C5 | 650°C | High-sulfur crude |
| F9 | 9Cr-1Mo | A335 P9 | A217 C12 | 650°C | Power, refinery |
| F91 | 9Cr-1Mo-V | A335 P91 | A217 C12A | 650°C | Supercritical steam |
| F304 | 18Cr-8Ni | A312 TP304 | A351 CF8 | 538°C | Corrosive service |
| F316 | 16Cr-10Ni-2Mo | A312 TP316 | A351 CF8M | 538°C | Chloride/marine |
| F304L | 18Cr-8Ni (low C) | A312 TP304L | A351 CF3 | 425°C | Welded assemblies |
| F316L | 16Cr-10Ni-2Mo (low C) | A312 TP316L | A351 CF3M | 425°C | Welded, corrosive |
| F321 | 18Cr-10Ni-Ti | A312 TP321 | - | 538°C | High-temp stainless |
| F51 | 22Cr-5Ni-3Mo (Duplex) | A790 S31803 | A995 4A | 315°C | Offshore, sour |
Alloy Steel Grades (F11, F22, F5, F9, F91)
These chrome-moly grades provide creep strength and oxidation resistance at temperatures above the 425°C limit of carbon steel. They match ASTM A335 alloy pipes and ASTM A217 cast valve bodies. Heat treatment is mandatory: normalize and temper, or quench and temper. A182 F11 is the most common grade for refinery high-temperature service.
Stainless Steel Grades (F304, F316, F321)
Austenitic stainless grades provide corrosion resistance from cryogenic (-254°C) to 538°C. F304 vs F316 is the most common selection decision: F316’s molybdenum content provides superior pitting resistance in chloride environments. Solution annealing is required for all austenitic grades.
Mechanical Properties (Selected Grades)
| Grade | Tensile (min) | Yield (min) | Elongation (min) | Hardness (max) |
|---|---|---|---|---|
| F11 Cl.2 | 485 MPa | 275 MPa | 20% | 197 HBW |
| F22 Cl.3 | 515 MPa | 310 MPa | 20% | 197 HBW |
| F304 | 515 MPa | 205 MPa | 30% | 183 HBW |
| F316 | 515 MPa | 205 MPa | 30% | 183 HBW |
| F51 | 620 MPa | 450 MPa | 25% | 293 HBW |
Testing and Certification
ASTM A182 requires chemical analysis, tensile testing, hardness testing, and heat treatment per grade. Mill test certificates document all results. Supplementary requirements include impact testing, ultrasonic and magnetic particle examination, hydrostatic testing, and intergranular corrosion testing (for austenitic grades per ASTM A262). The forging process produces a refined grain structure superior to castings for fatigue and impact resistance.
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