ASTM A194 Suppliers, Manufacturers
This specification covers a variety of carbon, alloy, and martensitic and austenitic stainless steel nuts. These nuts are intended for high-pressure or high-temperature service, or both. Bars from which the nuts are made shall be hot-wrought. The material may be further processed by centerless grinding or by cold drawing. Austenitic stainless steel may be solution annealed or annealed and strain-hardened. Each alloy shall conform to the chemical composition requirements prescribed. Hardness tests, proof of load tests, and cone proof load tests shall be made to all nuts to meet the requirements specified.
Grades Covered Under Astm A194
| 2 | Carbon steel heavy hex nuts |
|---|---|
| 2H | Quenched & tempered carbon steel heavy hex nuts |
| 2HM | Quenched & tempered carbon steel heavy hex nuts |
| 4 | Quenched & tempered carbon-molybdenum heavy hex nuts |
| 7 | Quenched & tempered alloy steel heavy hex nuts |
| 7M | Quenched & tempered alloy steel heavy hex nuts |
| 8 | Stainless AISI 304 heavy hex nuts |
| 8M | Stainless AISI 316 heavy hex nuts |
Mechanical Properties
Nut -Grade Identification Markings
All markings shown for all grades of A194 are for cold formed and for hot forged nuts. When nuts are machined from bar stock, the nut must additionally be marked with the letter "B"
| Grade Identification Marking5 | Specification | Material | Nominal Size, In. | Tempering Temp. °F | Proof Load Stress, ksi | Hardness Rockwell | See Note | |
|---|---|---|---|---|---|---|---|---|
| Min | Max | |||||||
 | ASTM A194 Grade 2 | Medium Carbon Steel | 1/4 - 4 | 1000 | 150 | 159 | 352 | 1,2,3 |
 | ASTM A194 Grade 2H | Medium Carbon Steel, Quenched and Tempered | 1/4 - 4 | 1000 | 175 | C24 | C38 | 1,2 |
 | ASTM A194 Grade 2HM | Medium Carbon Steel, Quenched and Tempered | 1/4 - 4 | 1000 | 150 | 159 | 237 | 1,2,3 |
 | ASTM A194 Grade 4 | Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 - 4 | 1100 | 175 | C24 | C38 | 1,2 |
 | ASTM A194 Grade 7 | Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 - 4 | 1100 | 175 | C24 | C38 | 1,2 |
 | ASTM A194 Grade 7M | Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 - 4 | 1100 | 150 | 159 | 237 | 1,2,3 |
 | ASTM A194 Grade 8 | Stainless AISI 304 | 1/4 - 4 | - | 80 | 126 | 300 | 4 |
 | ASTM A194 Grade 8M | Stainless AISI 316 | 1/4 - 4 | - | 80 | 126 | 300 | 4 |