ASTM A194 Grade 7L heavy hex nuts are manufactured from alloy steel, quenched and tempered. The ASTM A194 specification covers carbon steel, alloy steel, and stainless steel nuts for bolts in high pressure or high temperature service, and A194 nuts are frequently used in these demanding applications. They are a common high strength nut used with stud bolts for high and low temperature service, such as B16 and L7, and are closely related to other ASTM A194 Grade 7 components used across similar environments. When low temperature requirements are specified for Grade 7 nuts, the Charpy test procedures and requirements as defined in Specification A320/A320M for Grade L7 will apply. Grade markings consist of the grade symbol "7L". Dimensional specifications are governed by ASME B18.2.2. Heavy hex nuts provide increased bearing surface area over finished nuts such as J995 Grade 5 nuts.