ANSI B18.8

Description / Abstract: This standard is intended for use in high strength applications, such as steam turbine work, where fasteners are subjected to high temperatures of the order of 800 to 900 F fot long periods of time. In comparison with standard socket head screws that are widely used for general purposes, this standard covers fasteners with larger head proportions to provide greater area on the bearing surface of the head and to assure greater strength in the head and wrenches than in the body or threaded portion of the bolt in view of materials and other factors involved. The bolts have cylindrical heads to permit spot peening of the top of the head in a counterbore where this method of locking is desired.