Bolt Grade Rating

SAE Grade No.

Size Range

Tensile Strength

Material

Head Marking

Grade 2

¼” thru ¾”

⅞” thru 1 ½”

74,000 psi

60,000 psi

Low or medium carbon steel.

Grade 3

¼” thru ¾”

110,000 psi

Medium carbon steel

Grade 5

¼” thru 1”

120,000 psi

Medium carbon steel, quenched & tempered

Grade 5.1

¼” thru ½”

120,000 psi

Lor or medium carbon steel, quenched & tempered

Grade 6

¼” thru 1”

140,000 psi

Medium carbon steel, quenched & tempered

Grade 8

¼” thru 1 ½”

150,000 psi

Medium carbon alloy steel, quenched & tempered