2H Heavy Hex Nut

2H Heavy Hex Nut

The ASTM A194 specification covers carbon, alloy and stainless steel nuts intended for use in high-pressure and/or high-temperature service. Unless otherwise specified, the American National Standard Heavy Hex Series (ANSI B 18.2.2) shall be used. Nuts up to and including 1 inch nominal size shall be UNC Series Class  2B fit. Nuts over 1 inch nominal size shall be either UNC Series Class 2B fit or 8 UN Series Class 2B fit. High strength ASTM A194 grade 2H nuts are common in the marketplace and are often substituted for ASTM A563 grade DH nuts due to the limited availability of DH nuts in certain diameters and finishes.

A194 Grades

2 Carbon steel heavy hex nuts
2H Quenched & tempered carbon steel heavy hex nuts
2HM Quenched & tempered carbon steel heavy hex nuts, 100% hardness tested
4 Quenched & tempered carbon-molybdenum heavy hex nuts
7 Quenched & tempered alloy steel heavy hex nuts
7M Quenched & tempered alloy steel heavy hex nuts, 100% hardness tested
7L Quenched & tempered alloy steel heavy hex nuts, Charpy impact tested
8 Stainless AISI 304 heavy hex nuts
8M Stainless AISI 316 heavy hex nuts