ASTM A354

ASTM A354 is an ASTM International standard that defines chemical and mechanical properties for alloy steel bolts, screws, studs, and other externally threaded fasteners. It is officially titled: Standard Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners.^[1]

This is a standard set by the standards organization ASTM International, a voluntary standards development organizations that sets technical standards for materials, products, systems, and services.

Mechanical properties

This standard defines the properties for fasteners up to 4 inches in diameter. They are not to be used in applications where they are tensioned to more than 50% of their tensile strength. In those applications structural heavy hex bolts are to be used, as defined by ASTM A490, even though they have the same strength.^[1][2]

Head markings and mechanical properties^[3]

Head marking	Grade	Nominal size range [in]	Proof strength [ksi]	Yield strength (min) [ksi]	Tensile strength (min) [ksi]	Core hardness [Rockwell]
	Grade BC	1⁄4–2-1⁄2 (inc.)	105	109	125	C26–36
		2-1⁄2–4	95	99	115	C22–33
	Grade BD	1⁄4–2-1⁄2 (inc.)	120	130	150	C33–39
		2-1⁄2–4	105	115	140	C31–39

Recommended nuts

The standard also specifies what nuts are recommended for use with the defined fasteners. Note that nuts of a greater strength can also be used.^[1]

Fastener grade & surface finish	Nut grade & style
BC; plain or a coating of insufficient thickness to require over-tapped nuts	C; heavy hex
BC; zinc-coated or a coating that requires over-tapped nuts	DH; heavy hex
BD; all finishes	DH; heavy hex