ASTM, SAE AND ISO GRADE MARKINGS AND MECHANICAL PROPERTIES FOR STEEL FASTENERSIdentificationGrade MarkSpecificationFastenerDescriptionMaterialNominal SizeRange (in.)Mechanical Properties

Proof Load(psi)Yield StrengthMin (psi)Tensile StrengthMin (psi)

NoGradeMarkSAE J429Grade 1Bolts, Screws, StudsLow or Medium Carbon Steel1/4 thru 1-1/233,00036,00060,000

ASTM A307Grades A&BLow Carbon Steel1/4 thru 4----

SAE J429Grade 2Low or Medium Carbon Steel1/4 thru 3/4 Over 3/4 to 1-1/255,00033,00057,00036,00074,00060,000

NoGradeMarkSAE J429Grade 4StudsMedium Carbon Cold Drawn Steel1/4 thru 1-1/2--100,000115,000

B5ASTM A193Grade B5AISI 5011/4 Thru 4--80,000100,000

B6ASTM A193Grade B6AISI 41085,000110,000

B7ASTM A193Grade B7AISI 4140, 4142, OR 41051/4 thru 2-1/2 Over 2-1/2 thru 4Over 4 thru 7------105,00095,00075,000125,000115,000100,000

B16ASTM A193Grade B16CrMoVa Alloy Steel105,00095,00085,000125,000115,000100,000

B8ASTM A193Grade B8AISI 3041/4 and larger--30,00075,000

B8CASTM A193Grade B8CAISI 347

B8MASTM A193Grade B8MAISI 316

B8TASTM A193Grade B8TBolts,Screws,Studs for High-Temperature ServiceAISI 3211/4 and larger--30,00075,000

B8ASTM A193Grade B8AISI 304Strain Hardened1/4 thr 3/4Over 3/4 thru 1Over 1 thru 1-1/4Over 1-1/4 thru 1-1/2--------100,00080,00065,00050,000125,000115,000105,000100,000

B8CASTM A193Grade B8CAISI 347Strain Hardened

B8MASTM A193Grade B8MAISI 316Strain Hardened95,00080,00065,00050,000110,000100,00095,00090,000

B8TASTM A193Grade B8TAISI 321Strain Hardened100,00080,00065,00050,000125,000115,000105,000100,000

L7ASTM A320Grade L7Bolts,Screws,Studs for Low-Temperature ServiceAISI 4140,4142 or 41451/4 thru 2-1/2 --105,000125,000

L7AASTM A320Grade L7AAISI 4037

L7BASTM A320Grade L7BAISI 4137

L7CASTM A320Grade LC7AISI 8740

L43ASTM A320Grade L43AISI 43401/4 thru 4--105,000125,000

B8ASTM A320Grade B8Bolts,Screws,Studs for Low-Temperature ServiceAISI 3041/4 and larger--30,00075,000

B8CASTM A320Grade B8CAISI 347

B8TASTM A320Grade B8TAISI 321

B8FASTM A320Grade B8FAISI 303or 303Se

B8MASTM A320Grade B8MAISI 316

B8ASTM A320Grade B8AISI 3041/4 thru 3/4Over 3/4 thru 1Over 1 thru 1-1/4Over 1-1/4 thru 1-1/2--------100,00080,00065,0050,00100,00080,00065,0050,00

B8CASTM A320Grade B8CAISI 347

B8FASTM A320Grade B8FAISI 303or 303Se

B8MASTM A320Grade B8MAISI 316

B8TASTM A320Grade B8TAISI 321

SAE J429Grade 5Bolts,Screws,StudsMedium Carbon Steel, Quenched and Tempered1/4 thru 1Over 1 to 1-1/285,00074,00092,00081,000120,000105,000

ASTM A4491/4 thru 1Over 1 to 1-1/2Over 1-1/2 thru 385,00074,00055,00092,00081,00058,000120,000105,00090,000

SAE J429Grade 5.1SemsLow or Medium Carbon Steel, Quenched and TemperedNo. 6thru 3/885,000--120,000

SAE J429Grade 5.2Bolts,Screws,StudsLow Carbon Martensitic Steel, Quenched and Tempered1/4 thru 185,00092,000120,000

A325ASTM A325Type 1High StrengthStructural BoltsMedium Carbon Steel, Quenched and Tempered1/2 thru 11-1/8 thru 1-1/285,00074,00092,00081,000120,000105,000

A325ASTM A325Type 2Low Carbon Martensitic Steel, Quenched and Tempered1/2 thru 185,00092,000120,000

A325ASTM A325Type 3Atmospheric Corrosion Resisting Steel, Quenched and Tempered1/2 thru 11-1/8 thru 1-1/285,00074,00092,00081,000120,000105,000

BBASTM A354Grade BBBolts,StudsAlloy Steel, Quenched and Tempered1/4 thru 2-1/22-3/4 thru 480,00075,00083,00078,000105,000100,000

BCASTM A354Grade BC105,00095,000109,00099,000125,000115,000

SAE J429Grade 7Bolts,Screws,Medium Carbon Alloy Steel, Quenched and Tempered 41/4 thru 1-1/2105,000115,000133,000

SAE J429Grade 8Bolts,Screws,StudsMedium Carbon Alloy Steel, Quenched and Tempered1/4 thru 1-1/2120,000130,000150,000

ASTM A354Grade BDAlloy Steel, Quenched and Tempered 4

No GradeMarkSAE J429Grade 8.1StudsMedium Carbon Alloy or SAE 1041 Modified Elevated Temperature Drawn Steel1/4 thru 1-1/2120,000130,000150,000

A490ASTM A490High Strength Structural BoltsAlloy Steel, Quenched and Tempered1/2 thru 1-1/2120,000130,000150,000 min170,000 max

No GradeMarkISO R898Class 4.6Bolts,Screws,StudsMedium Carbon Steel, Quenched and TemperedAll Sizesthru 1-1/233,00036,00060,000

No GradeMarkISO R898Class 5.855,00057,00074,000

8.8

or

88ISO R898Class 8.8Alloy Steel, Quenched and Tempered85,00092,000120,000

10.9

or

109ISO R898Class 10.9120,000130,000150,000

FASTENER IDENTIFICATION MARKINGGradeIdentificationMarkingSpecificationMaterialNominal SizeIn.ProofLoadStressksiHardnessRockwellSeeNote

MinMax

No MarkASTM A563 - Grade 0Carbon Steel1/4 thru 1-1/269B55C323,4

ASTM A563 - Grade ACarbon Steel1/4 thru 1-1/290B68C323,4

ASTM A563 - Grade BCarbon Steel1/4 thru 1120B69C323,4

over 1 thru 1-1/2105

ASTM A563 - Grade CCarbon SteelMay be Quenchedand Tampered1/4 thru 4144B78C385

ASTM A563 - Grade C3AtmosphericCorrosionResistant SteelMay be Quenchedand Tampered1/4 thru 4144B78C385,9

ASTM A563 - Grade DCarbon SteelMay be Quenchedand Tampered1/4 thru 4150B84C386

ASTM A563 - Grade DHCarbon SteelQuenchedand Tampered1/4 thru 4175C24C386

ASTM A563 - Grade DH3AtmosphericCorrosionResistant Steel,Quenchedand Tampered1/4 thru 4175C24C385,9

ASTM A194 - Grade 1Carbon Steel1/4 thru 4130B70--7

ASTM A194 - Grade 2Medium CarbonSteel1/4 thru 41501593527,8

ASTM A194 - Grade 2HMedium CarbonSteel, Quenchedand Tempered1/4 thru 4175C24C387

ASTM A194 - Grade 2HMMedium CarbonSteel, Quenchedand Tempered1/4 thru 41501592377,8

ASTM A194 - Grade 4Medium CarbonAlloy Steel,Quenchedand Tempered1/4 thru 4175C24C387

ASTM A194 - Grade 7Medium CarbonAlloy Steel,Quenchedand Tempered1/4 thru 4175C24C387

ASTM A194 - Grade 7MMedium CarbonAlloy Steel,Quenchedand Tempered1/4 thru 41501592377

See Note 1,210

NOTES:1. In addition to the indicated grade marking, all grades, except A563 grades O, A and B, must be marked for manufacturer identification. 2. The markings shown for all grades of A194 nuts are for cold formed and hot forged nuts. When nuts are machined from bar stock the nut must be additionally marked with the letter 'B'. 3. Nuts are not required to be marked unless specified by the purchaser. When marked, the identification marking shall be the grade letter O, A or B. 4. Properties shown are those of nonplated or noncoated coarse thread hex nuts. 5. Properties shown are those of coarse thread heavy hex nuts. 6. Properties shown are those of coarse thread heavy hex nuts. 7. Properties shown are those of coarse 8-pitch thread heavy hex nuts. 8. Hardnesses are Brinell Hardness Numbers. 9. The nut manufacturer, at his option, may add other markings to indicate the use of atmospheric corrosion resistant steel. 10. Specifications --ASTM A563 -- Carbon and Alloy Steel Nuts.ASTM A194/A194M -- Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service.

Bolt Grade Markings and Strength ChartHead Marking Grade andMaterialNominal Size Range(inches)Mechanical Properties

Proof Load(psi)Min. Yield Strength(psi)Min. Tensile Strength(psi)

US Bolts

No MarkingsGrade 2Low or medium carbon steel1/4 thru 3/455,00057,00074,000

Over 3/4 thru 1-1/233,00036,00060,000

3 Radial LinesGrade 5Medium Carbon Steel, Quenched and Tempered1/4 thru 185,00092,000120,000

Over 1 thru 1-1/274,00081,000105,000

6 Radial LinesGrade 8Medium Carbon Alloy Steel, Quenched and Tempered1/4 thru 1-1/2120,000130,000150,000

Stainless markings vary. Most stainless is non-magnetic18-8 StainlessSteel alloy with 17-19% Chromium and 8-13% Nickel1/4 thru 5/840,000 Min. 80,000 90,000 Typical100,000 125,000 Typical

3/4 thru 140,000 Min. 45,000 70,000 Typical100,000 Typical

Above 180,000 90,000 Typical

Head MarkingClass andMaterialNominal Size Range(mm)Mechanical Properties

Proof Load(MPa)Min. Yield Strength(MPa)Min. Tensile Strength(MPa)

Metric bolts

8.8Class 8.8Medium Carbon Steel, Quenched and TemperedAll Sizes below 16mm580640800

16mm - 72mm 600660830

10.9Class 10.9Alloy Steel, Quenched and Tempered5mm - 100mm8309401040

12.9Class 12.9Alloy Steel, Quenched and Tempered1.6mm - 100mm97011001220

Stainless markings vary. Most stainless is non-magnetic.Usually stamped A-2 A-2 StainlessSteel alloy with 17- 19% Chromium and 8-13% NickelAll Sizes thru 20mm210 Min.450 Typical 500 Min.700 Typical

Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.Yield Strength: The maximum load at which a material exhibits a specific permanent deformationProof Load: An axial tensile load which the product must withstand without evidence of any permanent set.1MPa = 1N/mm2 = 145 pounds/inch2