Bolt Markings

ASTM, SAE AND ISO GRADE MARKINGS AND MECHANICAL PROPERTIES FOR STEEL FASTENERS

 

 

Item Name

Fastener Class

Material

Nominal Size
Range
(in.)

Mechanical Properties

Proof Load
(psi)

Yield Strength
Min (psi)

Tensile Strength
Min (psi)


No
Grade
Mark

SAE J429
Grade 1

Bolts,
Screws,
Studs

Low or Medium Carbon Steel

1/4 thru 1-1/2

33,000

36,000

60,000

ASTM A307
Grades A&B

Low Carbon Steel

1/4 thru 4

SAE J429
Grade 2

Low or Medium Carbon Steel

1/4 thru 3/4 Over 3/4 to 1-1/2

55,000
33,000

57,000
36,000

74,000
60,000

No
Grade
Mark

SAE J429
Grade 4

Studs

Medium Carbon Cold Drawn Steel

1/4 thru 1-1/2

100,000

115,000


B5

ASTM A193
Grade B5

AISI 501

1/4 Thru 4

80,000

100,000


B6

ASTM A193
Grade B6

AISI 410

85,000

110,000


B7

ASTM A193
Grade B7

AISI 4140, 4142, OR 4105

1/4 thru 2-1/2
Over 2-1/2 thru 4
Over 4 thru 7



105,000
95,000
75,000

125,000
115,000
100,000


B16

ASTM A193
Grade B16

CrMoVa Alloy Steel

105,000
95,000
85,000

125,000
115,000
100,000


B8

ASTM A193
Grade B8

AISI 304

1/4 and larger

30,000

75,000


B8C

ASTM A193
Grade B8C

AISI 347


B8M

ASTM A193
Grade B8M

AISI 316


B8T

ASTM A193
Grade B8T

Bolts,
Screws,
Studs for High-Temp Service

AISI 321

1/4 and larger

30,000

75,000


B8

ASTM A193
Grade B8

AISI 304
Strain Hardened

1/4 thr 3/4
Over 3/4 thru 1
Over 1 thru 1-1/4
Over 1-1/4 thru 1-1/2




100,000
80,000
65,000
50,000

125,000
115,000
105,000
100,000


B8C

ASTM A193
Grade B8C

AISI 347
Strain Hardened


B8M

ASTM A193
Grade B8M

AISI 316
Strain Hardened

95,000
80,000
65,000
50,000

110,000
100,000
95,000
90,000


B8T

ASTM A193
Grade B8T

AISI 321
Strain Hardened

100,000
80,000
65,000
50,000

125,000
115,000
105,000
100,000


L7

ASTM A320
Grade L7

Bolts,
Screws,
Studs for Low-Temp Service

AISI 4140,
4142 or 4145

1/4 thru 2-1/2

105,000

125,000


L7A

ASTM A320
Grade L7A

AISI 4037


L7B

ASTM A320
Grade L7B

AISI 4137


L7C

ASTM A320
Grade LC7

AISI 8740


L43

ASTM A320
Grade L43

AISI 4340

1/4 thru 4

105,000

125,000


B8

ASTM A320
Grade B8

Bolts,
Screws,
Studs for Low-Temp Service

AISI 304

1/4 and larger

30,000

75,000


B8C

ASTM A320
Grade B8C

AISI 347


B8T

ASTM A320
Grade B8T

AISI 321


B8F

ASTM A320
Grade B8F

AISI 303
or 303Se


B8M

ASTM A320
Grade B8M

AISI 316


B8

ASTM A320
Grade B8

AISI 304

1/4 thru 3/4
Over 3/4 thru 1
Over 1 thru 1-1/4
Over 1-1/4 thru 1-1/2




100,000
80,000
65,00
50,00

100,000
80,000
65,00
50,00


B8C

ASTM A320
Grade B8C

AISI 347


B8F

ASTM A320
Grade B8F

AISI 303
or 303Se


B8M

ASTM A320
Grade B8M

AISI 316


B8T

ASTM A320
Grade B8T

AISI 321

 

SAE J429
Grade 5

Bolts,
Screws,
Studs

Medium Carbon Steel, Quenched and Tempered

1/4 thru 1
Over 1 to 1-1/2

85,000
74,000

92,000
81,000

120,000
105,000

ASTM A449

1/4 thru 1
Over 1 to 1-1/2
Over 1-1/2 thru 3

85,000
74,000
55,000

92,000
81,000
58,000

120,000
105,000
90,000

 

SAE J429
Grade 5.1

Sems

Low or Medium Carbon Steel, Quenched and Tempered

No. 6
thru 3/8

85,000

120,000

 

SAE J429
Grade 5.2

Bolts,
Screws,
Studs

Low Carbon Martensitic Steel, Quenched and Tempered

1/4 thru 1

85,000

92,000

120,000


A325

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


A325

ASTM A325
Type 2

Low Carbon Martensitic Steel, Quenched and Tempered

1/2 thru 1

85,000

92,000

120,000


A325

ASTM A325
Type 3

Atmospheric Corrosion Resisting 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


BB

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


BC

ASTM A354
Grade BC

105,000
95,000

109,000
99,000

125,000
115,000

 

SAE J429
Grade 7

Bolts,
Screws,

Medium Carbon Alloy Steel, Quenched and Tempered 4

1/4 thru 1-1/2

105,000

115,000

133,000

 

SAE J429
Grade 8

Bolts,
Screws,
Studs

Medium Carbon Alloy Steel, Quenched and Tempered

1/4 thru 1-1/2

120,000

130,000

150,000

ASTM A354
Grade BD

Alloy Steel, Quenched and Tempered 4


No Grade
Mark

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


A490

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

No Grade
Mark

ISO R898
Class 4.6

Bolts,
Screws,
Studs

Medium Carbon Steel, Quenched and Tempered

All Sizes
thru 1-1/2

33,000

36,000

60,000


No Grade
Mark

ISO R898
Class 5.8

55,000

57,000

74,000

8.8

or

88

ISO R898
Class 8.8

Alloy Steel, Quenched and Tempered

85,000

92,000

120,000

10.9

or

109

ISO R898
Class 10.9

120,000

130,000

150,000

 

FASTENER IDENTIFICATION MARKING

Grade
Marking

Item Name

Material

Nominal Size
In.

Proof
Load
Stress
ksi

Hardness
Rockwell

See
Note

Min

Max


No Mark

ASTM A563 – Grade 0

Carbon Steel

1/4 thru 1-1/2

69

B55

C32

3,4

ASTM A563 – Grade A

Carbon Steel

1/4 thru 1-1/2

90

B68

C32

3,4

ASTM A563 – Grade B

Carbon Steel

1/4 thru 1

120

B69

C32

3,4

over 1 thru 1-1/2

105

 

ASTM A563 – Grade C

Carbon Steel
May be Quenched
and Tampered

1/4 thru 4

144

B78

C38

5

 

ASTM A563 – Grade C3

Corrosion
Resistant Steel
May be Quenched
and Tampered

1/4 thru 4

144

B78

C38

5,9

 

ASTM A563 – Grade D

Carbon Steel
May be Quenched
and Tampered

1/4 thru 4

150

B84

C38

6

 

ASTM A563 – Grade DH

Carbon Steel
Quenched
and Tampered

1/4 thru 4

175

C24

C38

6

 

ASTM A563 – Grade DH3

Corrosion
Resistant Steel,
Quenched
and Tampered

1/4 thru 4

175

C24

C38

5,9

 

ASTM A194 – Grade 1

Carbon Steel

1/4 thru 4

130

B70

7

 

ASTM A194 – Grade 2

Medium Carbon
Steel

1/4 thru 4

150

159

352

7,8

 

ASTM A194 – Grade 2H

Medium Carbon
Steel, Quenched
and Tempered

1/4 thru 4

175

C24

C38

7

 

ASTM A194 – Grade 2HM

Medium Carbon
Steel, Quenched
and Tempered

1/4 thru 4

150

159

237

7,8

 

ASTM A194 – Grade 4

Medium Carbon
Alloy Steel,
Quenched
and Tempered

1/4 thru 4

175

C24

C38

7

ASTM A194 – Grade 7

Medium Carbon
Alloy Steel,
Quenched
and Tempered

1/4 thru 4

175

C24

C38

7

 

ASTM A194 – Grade 7M

Medium Carbon
Alloy Steel,
Quenched
and Tempered

1/4 thru 4

150

159

237

7

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