Commonly Hexagonal Heavy-series nuts used with studs. The non-bearing face of a nut is chamfered, while load Bearing face is finished with a washer face or may be chamfered.
Nuts may be machined from the same material as stud or may be of a compatible grade of ASTM A194
ASTM A194 standard lists the compatible material grades for nuts that used with stud & bolt.
Most widely used material grades are ASTM A194 Gr 2,2H,2HM,8,8M