CURABITUR ALIQUET QUAM POSUERE
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Grade | A194 Grade 7M |
Standard | ASTM A194/194M-2016 |
Carbon steel, Alloy steel, and Stainless steel nuts for bolts for high pressure or high temperature service, or both | |
Classification | Alloy steel |
Label | Type 4140,Type 4142,Type 4145,Type 4140H,Type 4142H,Type 4145H |
Introductions | 7HM nuts shall be made from hot or cold forging, or from hot-forged, hot-rolled, cold-drawn bar materials, and shall be heat-treated to meet the requirements of mechanical properties. This grade shall be uniformly reheated to the appropriate austenite temperature (a group of such reheating is called a quenching batch), and each quenching batch is quenched under basically uniform conditions, and then tempered, the heat treatment system is quenched in liquid; Minimum tempering temperature 1150°F(620°C). Nuts made of bar material treated according to this standard do not need to be re-treated. For nuts of 7HM, the final stress relief heat treatment is carried out after all forming operations, maching and tapping at a temperature higher than or equal to this minimum tempering temperature. Scope of application of this standard ① This standard is applicable to all kinds of carbon steel, alloy steel and martensitic stainless steel nuts of 1/4 to 4 inches and M6 to M100. Also applicable to austenitic stainless steel nuts of 1/4 inch and M6 and above. These nuts are suitable for high or high pressure or high temperature and high pressure environments. Nut grades may not be changed without Buyer’s permission. ② The bar material for making nuts should be hot forged. The material can be further processed by centerless grinding or cold drawing. Austenitic stainless steels can be solution treated or annealed and strain hardened. When ordering annealed and strain-hardened austenitic stainless steel in accordance with Supplemental Requirement S1, Buyer shall take special care to fully understand the contents of Supplemental requirement S1 and Appendix X1. Supplementary requirements are optional and apply only if specified in the inquiry, contract and order. |
A194 Grade 7M Chemical Element Content (%) | |||||||
Constituent | C | Si | Mn | P | S | Cr | Mo |
Min | 0.38 | 0.15 | 0.75 | – | – | 0.8 | 0.15 |
Max | 0.48 | 0.35 | 1 | 0.035 | 0.04 | 1.1 | 0.25 |
• Intentional addition of Bi, Se, Te and Pb is not allowed except for 6F, 8F and 8FA grades where Se is required. • grade 7M refers to the nut label; This standard specifies materials 4140H, 4142H, 4145H, 4140, 4142, 4145 manufacturing • Elements Ni, Ti, Cb, N not listed in the table are not required and do not need to be determined and reported. |
A194 Grade 7M Mechanical properties | |
Products | Hardness HRB |
Finished nut | 159~235HBW 84~99HRB |
Finished nut after heat treatment | ≥159HBW ≥84HRB |