The most common SAE bolt grades are Grade 2, Grade 5, and Grade 8.
Metric Bolt Grades Chart with Strength Chart
The most common bolt grades are 8.8, 10.9, and 12.9.
What Are These Numbers?
Bolts are made at different strengths. The bolt grade markings are illustrated in the charts. They show examples of the typical bolt grade markings for each bolt grade. In addition, we give the material the bolt is made from as well as its hardness range.
Here is how the bolt strength is specified:
Tensile Strength: The maximum load in tension which a material can withstand before fracturing.
Yield Strength: The maximum load at which a material exhibits permanent deformation.
Proof Load: An axial tensile load which the bolt must withstand without evidence of any permanent deformation. An acceptable clamp load is 75% of the Proof Load.
Download PDFs of these Bolt Marking Charts
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Recently updated on November 21st, 2023 at 11:03 am
Bob is responsible for the development and implementation of the popular G-Wizard CNC Software. Bob is also the founder of CNCCookbook, the largest CNC-related blog on the Internet.
