ASTM A193 Grade B7 stud bolts are high strength fasteners manufactured from a chromium-molybdenum steel and are quenched and tempered. Dimensional specifications are governed by ASME B18.31.2. Grade markings consists of both the grade symbol "B7" and the manufacturer's identification mark on one end of each stud 3/8" diameter and larger. Manufacturer's marking may be placed on other end if insufficient space. Inch series fasteners meeting ASTM A193 Grade B7 specifications are typically used in flange bolting applications. ASTM A193 covers the requirements for high temperature and high pressure bolting. A193 B7 all thread studs, as well as hex bolts having diameters above 1" are most common 8UN (8 threads per inch).