Engineering:ASTM A354

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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]
Hex cap screw-ASTM A354 grade BC.svg Grade BC
14–2-​12 (inc.) 105 109 125 C26–36
2-​12–4 95 99 115 C22–33

Hex cap screw-ASTM A354 grade BD lines.svg
Grade BD 14–2-​12 (inc.) 120 130 150 C33–39
Hex cap screw-ASTM A354 grade BD.svg 2-​12–4 105 115 140 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

References