ASTM A182 Grade F22 (UNS K21590)
Grade: ASTM A182 Grade F22 (UNS K21590), also known as 2 1/4 Cr. 1Mo
Type: Alloy Steel usually used in the hardened, quenched and tempered condition
| Nominal Composition | |
|---|---|
| Element | Weight % |
| Carbon | 0.08 – 0.15 |
| Silicon | 0.15 – 0.50 |
| Manganese | 0.30 – 0.60 |
| Phosphorus | 0.025 max * |
| Sulphur | 0.025 max * |
| Molybdenum | 0.90 – 1.10 |
| Chromium | 2.00 – 2.50 |
| Nickel | 0.5 max |
Notes
Various other analysis are available in order to improve properties
* These values conform with API 6A, PSL 3 requirements. Higher values may be permitted if delivered to alternative specifications
Mechanical Properties
Condition:
Hardened followed by oil or water quenching and tempering
Typical tempering range is 620 – 680o C, depending on properties required
| Property | Values |
|---|---|
| Ultimate Tensile Strength * | 95 min Ksi (655 Mpa) |
| 0.2 % Yield Strength * | 75 min Ksi (517 Mpa) |
| Elongation * | 17 % min |
| Reduction of Area * | 35 % min |
| Charpy Impact Toughness | 42 mean/ 33 min J at –18o C |
| Hardness | 197 – 237 BHN (75 Ksi min) |
Notes:
* Values shown are based on API 6A PSL 3 requirements.
Impact toughness values shown are those typically specified for the grade.
Minimum hardness is based on API 6A requirements. Maximum hardness shown is based on compliance with NACE MR0175 / ISO 15156.
Grade is typically used for pressure containing applications such as larger valve bodies, wellheads, connectors or pipework.
Very good weldability, and so may be readily welded to itself or weld inlayed. The grade does require a post weld heat treatment at 620oC min in order to meet sour service (NACE MR0175/ ISO 15156) requirements. The good weldability of the grade means that it is frequently used where welding is a requirement, such as for weld clad or inlaid components.
The grade has good ruling section of, typically up to 12 inches (at 75 ksi) depending on the composition and analysis, and it is critical that the hardenability of the grade must be taken into account when designing and selecting it for specific equipment. Its relatively high ruling section means that it is frequently used for large forgings.
There is also a higher carbon (0.15 – 0.20 %) carbon version of the grade.