Bolt identification 101 (1 Viewer)

[silverhorse]

I thought it might be a good idea to post up some info on bolt hardness. This may come in handy for those just getting into fab work or suspension upgrades. I always use grade 8 hardware AND LOCKING NUTS whenever doing anything on the chassis or suspension.
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Bolt Head Marking Chart​

Identification
Grade Mark Specifications Material Normal Size
Dia. In Proof Load
PSI
(Mpa) Tensile Strength
Min. PSI
(Mpa) Yield Strength
Min. PSI Bolt Rockwell
Hardness Nut Rockwell
Hardness Min Max Min Max

SAE J429
Grade 1 Low Carbon Steel 1/4" - 1 1/4" 33.000 60.000 36,000 B70 B100 SAE J429
Grade 2 1/4 " - 3/4"
3/4" - 1 1/2" 55.000
33.000 60.000
74.000 57.000
36.000 B80 B100 C32

Property
Class 5.8 Low or Medium
Carbon Steel M5 - M24 55.100
(380) 75.400
(520) B82 B95 C32

SAE J429
Grade 5 Medium Carbon Steel, Quenched and Tempered 1/4 - 1
1" - 1-1/2" 85,000
74,000 120,000
105,000 92,000
81,000 C25
C19 C34
C30 C32 ASTM A449 1/4" - 1"
1" - 1-1/2
1-1/2" - 3" 85,000
74,000
55,000 120,000
105,000
90,000 92,000
81,000
58,000

SAE J429
Grade 5.1 Low or Medium Carbon Steel, Quenched and Tempered No. 6
thru 3/8 85,000 120,000 C25 C40

SAE J429
Grade 5.2 Low Carbon Martensitic Steel, Quenched and Tempered 1/4 thru 1 85,000 120,000 92,000

ASTM A325
Type 1 Medium Carbon Steel, Quenched and Tempered 1/2 thru 1
1-1/8 thru 1-1/2 85,000
74,000 120,000
105,000 92,000
81,000

A325 ASTM A325
Type 2 Low Carbon Martensitic Steel, Quenched and Tempered 1/2 thru 1 85,000 120,000 92,000

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
74,000 120,000
105,000 92,000
81,000 Identification
Grade Mark Specifications Material Normal Size
Dia. In Proof Load
PSI
(Mpa) Tensile Strength
Min. PSI
(Mpa) Yield Strength
Min. PSI Bolt Rockwell
Hardness Nut Rockwell
Hardness Min Max Min Max

BB ASTM A354
Grade BB Alloy Steel, Quenched and Tempered 1/4 thru 2-1/2
2-3/4 thru 4 80,000
75,000 105,000
100,000 83,000
78,000

BC ASTM A354
Grade BC 105,000
95,000 125,000
115,000 109,000
99,000

Property
Class 9.8 Medium carbon steel, Quenched & tempered M1.6 - M16 94.250
(650) 130.500
(900) C27 C36 C32

SAE J429
Grade 7 Medium Carbon Alloy Steel, Quenched and Tempered 1/4 thru 1-1/2 105,000 133,000 115,000

SAE J429
Grade 8 Medium Carbon Alloy Steel, Quenched and Tempered 1/4 thru 1-1/2 120,000 150,000 130,000 ASTM A354
Grade BD Alloy Steel, Quenched and Tempered

No Grade
Mark SAE J429
Grade 8.1 Medium Carbon Alloy or SAE 1041 Modified Elevated Temperature Drawn Steel 1/4 thru 1-1/2 120,000 150,000 130,000

SAE
Grade 8.2 Low carbon boron martensite steel
fully killed fine grain quenched & tempered 1/4" - 1" 120.000 150.000 C35 C42 Identification
Grade Mark Specifications Material Normal Size
Dia. In Proof Load
PSI
(Mpa) Tensile Strength
Min. PSI
(Mpa) Yield Strength
Min. PSI Bolt Rockwell
Hardness Nut Rockwell
Hardness Min Max Min Max

A490 ASTM A490 Alloy Steel, Quenched and Tempered 1/2 thru 1-1/2 120,000 150,000 min
170,000 max 130,000

No Grade
Mark ISO R898
Class 4.6 Medium Carbon Steel, Quenched and Tempered All Sizes

thru 1-1/2 120,000 150,000 130,000

Property
Class 10.9 Medium carbon alloy steel
quenched & tempered M6 - M36 120.350
(830) 150.800
(1040) C33 C39 C26 C36

Property
Class 12.9 Medium carbon alloy steel
quenched & tempered M1.6 - M36 140.000
(970) 176.900
(1220) C38 C44 C26 C36

Mechanical
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