Metric Stainless Steel Bolt Strength Chart, Class 50, 70, 80 and 100
Click here - Printable Stainless Steel Strength Chart (PDF)
Printable Chart for easy comparison between Stainless Steel Metric Bolt Classes and US grades equivalents.
Head Markings |
Metric Bolt Class |
Mechanical Properties |
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LBF/In² (PSI) |
Min Yield (MPa) |
Min Tensile Strength (MPa) |
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Class 100 Strongest stainless steel but uncommon. |
145,030 |
800 |
1,000 |
 |
Class 80 - High Strength Strongest commercially available stainless. Close to SAE Grade 5. |
116,030 |
600 |
800 |
 |
Class 70 - Cold Worked Most common stainless steel fastener class. |
101,530 |
450 |
700 |
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Class 50 - Soft Default as formed. Not worked to further increase strength. |
72,520 | 210 | 500 |
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US/Imperial LBF/In²(PSI) |
Metric Mpa(N/mm²) |
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Chart for easy comparison of US / Metric screws and bolts. It is always a bit unusual to compare them as they use different measurement systems (PSI vs. Mpa). |
180,000 SAE Grade 8- 150,000 145,030 SAE Grade 5 - 120,000 116,000 101,530 75,420 SAE Grade 2 - 74,000 72,520 58,020 |
1,220 - Class 12.9 1,040 - Class 10.9 1,000 - Stainless 100 830 - Class 8.8 800 - Stainless 80 700 - Stainless 70 520 - Class 5.8 510 500 - Stainless 50 400 - Class 4.6 |
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Proof Load: An axial tensile load which the product must withstand without evidence of any permanent set.
Yield Strength: The maximum load at which a material exhibits a specific permanent deformation
1MPa = 1N/mm2 = 145 pounds/Inch2
Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.