Keywords: Fasteners; Steels; Mechanical properties of materials; Unalloyed steels; Alloy steels; Bolts ; Screws (bolts); Studs (fasteners); External-thread fasteners; Temperature; Thread pitch ; Dimensions; Designations; Mechanical testing ; Tensile strength; Elongation at fracture; Yield stress; Chemical composition; Compositional tolerances ; Tempering; Hardness; Physical properties of materials; Surface properties; Approval testing; Proof loading; Tensile testing; Hardness testing; Impact testing; Test equipment; Testing conditions ; Test specimens; Specimen preparation; Angles (geometry); Decarburization; Marking; Symbols ; Dimensional changes