ASTM A194 Grade 8 heavy hex nuts are manufactured from AISI 304 grade stainless steel to meet ASTM A194 Grade 8 material specifications. Dimensional specifications are governed by ASME B18.2.2. Grade identification markings for A194 Grade 8 stainless steel heavy hex nuts consists of the number 8 stamped on the nut face. Grade 8 stainless steel heavy hex nuts are intended for use in high-pressure and/or high-temperature service and are for use with ASTM A193 bolting of similar material, such as ASTM A193-B8 Class 1. Heavy hex nuts feature a larger and heavier hex pattern that provides increased bearing surface area over regular finished pattern hex nuts.