Technical Specification ASTM A193 Grade B7 Chromium Molybendum steel, normally AISI 4140, heat treated to 28-32Rockwell Hardness, 125,000 PSI tensile strength, 105, 000 PSI yield. It will hold it's strength to 1000 degrees F. This grade of studbolts are engineered to mate with ASTM A194 Grade 2H Heavy Hex Nuts. Features ASTM A193 B7 bolts are built to the requirements of numerous specifications and material design properties. To be more specific, B7 alloy steel is a high temperature grade of A-193. B7 steel is also a chrome moly steel with a minimum tensile strength of 125ksi.