Bolt Identification Marking

Written by Jerry Ratzlaff. Posted in Fastener

  • A bolt is threaded on one end only.
  • A bolt stud is threaded on both ends or the full length.
  • A stud is threaded on both ends. One end is over sized to fit a tapping hole tight. The other end is threaded for a nut.
Identification Grade MarkSpecificationFastener DescriptionMaterialNominal Size Range (in)Proof Load (psi)Min Yield Strength (psi)Min Tensile Strength (psi)
BOLT NO MARK.jpg SAE J429 Grade 1 Bolts, Screws, Studs Low or Medium Carbon Steel 1/4 thru 1 1/2 33,000 36,000 60,000
BOLT NO MARK.jpg ASTM A307 Grade A & B Bolts, Screws, Studs Low Carbon Steel 1/4 thru 4 - - 60,000
BOLT NO MARK.jpg SAE J429 Grade 2 Bolts, Screws, Studs Low or Medium Carbon Steel 1/2 thru 3/4

Over 3/4 thru 1 1/2

55,000

33,000

57,000

36,000

74,000

60,000

BOLT NO MARK.jpg SAE J429 Grade 4 Studs Medium Carbon Cold Drawn Steel 1/4 thru 1 1/2 - 100,000 115,000
BOLT B5.jpg ASTM A193 Grade B5 Bolts, Screws, Studs for High Temperature Service AISI 501 1/4 thru 4 - 80,000 100,000
BOLT B6.jpg ASTM A193 Grade B6 Bolts, Screws, Studs for High Temperature Service AISI 410 1/4 thru 4 - 85,000 110,000
BOLT B7.jpg ASTM A193 Grade B7 Bolts, Screws, Studs for High Temperature Service AISI 4140

AISI 4142


AISI 4145

1/4 thru 2 1/2

Over 2 1/2 thru 4

Over 4 thru 7

-

-

-

105,000

95,000

75,000

125,000

150.000

100,000

BOLT B16.jpg ASTM A193 Grade B16 Bolts, Screws, Studs for High Temperature Service CrMoVa

Alloy Steel

1/4 thru 2 1/2

Over 2 1/2 thru 4

Over 4 thru 7

-

-

-

105,000

95,000

85,000

125,000

150.000

100,000

BOLT B8.jpg ASTM A193 Grade B8 Bolts, Screws, Studs for High Temperature Service AISI 304 1/4 and larger - 30,000 75,000
BOLT B8C.jpg ASTM A193 Grade B8C Bolts, Screws, Studs for High Temperature Service AISI 347 1/4 and larger - 30,000 75,000
BOLT B8M.jpg ASTM A193 Grade B8M Bolts, Screws, Studs for High Temperature Service AISI 316 1/4 and larger - 30,000 75,000
BOLT B8T.jpg ASTM A193 Grade B8T Bolts, Screws, Studs for High Temperature Service AISI 321 1/4 and larger - 30,000 75,000
BOLT B8 U.jpg ASTM A193 Grade B8 Bolts, Screws, Studs for High Temperature Service AISI 304

Strain Handened

1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

125,000

150,000

105,000

100,000

BOLT B8C U.jpg ASTM A193 Grade B8C Bolts, Screws, Studs for High Temperature Service AISI 347

Strain Handened

1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

125,000

150,000

105,000

100,000

BOLT B8M U.jpg ASTM A193 Grade B8M Bolts, Screws, Studs for High Temperature Service AISI 316

Strain Handened

1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

95,000

80,000

65,000

50,000

110,000

100,000

95,000

90,000

BOLT B8T U.jpg ASTM A193 Grade B8T Bolts, Screws, Studs for High Temperature Service AISI 347

Strain Handened

1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

125,000

115,000

105,000

100,000

BOLT L7.jpg ASTM A320 Grade L7 Bolts, Screws, Studs for Low Temperature Service AISI 4140 AISI 4142 AISI 4145 1/4 thru 2 1/2 - 105,000 125,000
BOLT L7A.jpg ASTM A320 Grade L7A Bolts, Screws, Studs for Low Temperature Service AISI 4037 1/4 thru 2 1/2 - 105,000 125,000
BOLT L7B.jpg ASTM A320 Grade L7B Bolts, Screws, Studs for Low Temperature Service AISI 4137 1/4 thru 2 1/2 - 105,000 125,000
BOLT L7C.jpg ASTM A320 Grade L7C Bolts, Screws, Studs for Low Temperature Service AISI 8740 1/4 thru 2 1/2 - 105,000 125,000
BOLT L43.jpg ASTM A320 Grade L43 Bolts, Screws, Studs for Low Temperature Service AISI 4340 1/4 thru 4 - 105,000 125,000
BOLT B8.jpg ASTM A320 Grade B8 Bolts, Screws, Studs for Low Temperature Service AISI 304 1/4 and larger - 30,000 75,000
BOLT B8C.jpg ASTM A320 Grade B8C Bolts, Screws, Studs for Low Temperature Service AISI 347 1/4 and larger - 30,000 75,000
BOLT B8T.jpg ASTM A320 Grade B8T Bolts, Screws, Studs for Low Temperature Service AISI 321 1/4 and larger - 30,000 75,000
BOLT B8F.jpg ASTM A320 Grade B8F Bolts, Screws, Studs for Low Temperature Service AISI 303 or AISI 303Se 1/4 and larger - 30,000 75,000
BOLT B8M.jpg ASTM A320 Grade B8M Bolts, Screws, Studs for Low Temperature Service AISI 316 1/4 and larger - 30,000 75,000
BOLT B8 U.jpg ASTM A320 Grade B8 Bolts, Screws, Studs for Low Temperature Service AISI 304 1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

100,000

80,000

65,000

50,000

BOLT B8C U.jpg ASTM A320 Grade B8C Bolts, Screws, Studs for Low Temperature Service AISI 347 1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

100,000

80,000

65,000

50,000

BOLT B8T U.jpg ASTM A320 Grade B8T Bolts, Screws, Studs for Low Temperature Service AISI 316 1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

100,000

80,000

65,000

50,000

BOLT B8F U.jpg ASTM A320 Grade B8F Bolts, Screws, Studs for Low Temperature Service AISI 321 1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

100,000

80,000

65,000

50,000

BOLT B8M U.jpg ASTM A320 Grade B8M Bolts, Screws, Studs for Low Temperature Service AISI 303 or AISI 303Se 1/4 thru 3/4

Over 3/4 thru 1

Over 1 thru 1 1/4

Over 1 1/4thru 1 1/2

-

-

-

-

100,000

80,000

65,000

50,000

100,000

80,000

65,000

50,000

BOLT 3A.jpg SAE J429 Grade 5 Bolts, Screws, Studs Medium Carbon Steel, Quenched and Tempered 1/4 thru 1

Over 1 thru 1 1/2

85,000

74,000

92,000

81,000

120,000

105,000

BOLT 3A.jpg ASTM A449 Bolts, Screws, Studs Medium Carbon Steel, Quenched and Tempered 1/4 thru 1

Over 1 thru 1 1/2Over 1 1/2 thru 3

85,000

74,000

55,00

92,000

81,000

58,000

120,000

105,000

90,000

BOLT 3B.jpg SAE J429 Grade 5.1 Sems Low or Medium Carbon Steel, Quenched and Tempered #6 thru 3/82 85,000 - 120,000
BOLT 3C.jpg SAE J429 Grade 5.2 Sems Low Carbon Martensitic Steel, Quenched and Tempered 1/4 thru 1 92,000 - 120,000
BOLT A325.jpg ASTM A325 Type 1 High Strength Structural Bolts Medium Carbon Steel, Quenched and Tempered 1/2 thru 1

1 1/8 thru 1 1/2

85,000

74,000

92,000

81,000

120,000

105,000

BOLT A325 3C.jpg ASTM A325 Type 2 High Strength Structural Bolts Low Carbon Martensitic Steel, Quenched and Tempered 1/2 thru 1 85,000 92,000 120,000
BOLT A325 U.jpg ASTM A325 Type 2 High Strength Structural Bolts Atmospheric Corrosion Resistant Steel, Quenched and Tempered 1/2 thru 1

1 1/8 thru 1 1/2

85,000

74,000

92,000

81,000

120,000

105,000

BOLT BB.jpg ASTM A354 Grade BB Bolts, Studs Alloy Steel, Quenched and Tempered 1/4 thru 2 1/2

2 3/4 thru 4

80,000

75,000

83,000

78,000

105,000

100,000

BOLT BC.jpg ASTM A354 Grade BC Bolts, Studs Alloy Steel, Quenched and Tempered 1/4 thru 2 1/2

2 3/4 thru 4

105,000

95,000

109,000

99,000

125,000

115,000

BOLT 5A.jpg SAE J429 Grade 7 Bolts and Screws Medium Carbon Alloy Steel, Quenched and Tempered 1/4 thru 1 1/2 105,000 115,000 133,000
BOLT 6A.jpg SAE J429 Grade 8 Bolts, Screws, Studs Alloy Steel, Quenched and Tempered 1/4 thru 1 1/2 120,000 130,000 150,000
BOLT 6A.jpg ASTM A354 Grade BD Bolts, Screws, Studs Alloy Steel, Quenched and Tempered 1/4 thru 1 1/2 120,000 130,000 150,000
BOLT NO MARK.jpg SAE J429 Grade 8.1 Studs Medium Carbon Alloy or SAE 1041 Modified Elevated Temperature Drawn Steel 1/4 thru 1 1/2 120,000 130,000 150,000
BOLT A490.jpg ASTM A490 High Strength Structural Bolts Alloy Steel, Quenched and Tempered 1/2 thru 1 1/2 120,000 130,000 150,000 min

170,000 max

BOLT NO MARK.jpg ISO R898 Class 4.6 Bolts, Screws, Studs Low or Medium Carbon Steel, Quenched and Tempered All Sizes thru 1 1/2 33,000 36,000 60,000
BOLT NO MARK.jpg ISO R898 Class 5.8 Bolts, Screws, Studs Low or Medium Carbon Steel, Quenched and Tempered All Sizes thru 1 1/2 55,000 57,000 74,000
BOLT 8 8.jpg BOLT 88.jpg ISO R898 Class 8.8 Bolts, Screws, Studs Medium Carbon Steel, Quenched and Tempered All Sizes thru 1 1/2 85,000 92,000 120,000
BOLT 10 9.jpg BOLT 109.jpg ISO R898 Class 10.9 Bolts, Screws, Studs Medium Carbon Steel, Quenched and Tempered All Sizes thru 1 1/2 120,000 130,000 150,000