What Are the Different Grades of Bolts and How Can They be Used?

Last Updated on July 1, 2020 by Marsh Fasteners

Bolts are available in a wide variety of different grades, which usually indicate a bolt’s tensile strength. If you are new to the world of fasteners, you will probably like to know which grades of bolts are used for what applications. Here is a general breakdown:


  • SAE American Grades 


These grades start at grade 2 and go up to grade 8, which is the strongest SAE American Grade bolt available. 


  • Grade 2 


A grade 2 bolt is distinguished through its complete lack of markings and will usually have a tensile strength of between 60,000 and 74,000 psi. These bolts are generally used for non-critical joints and applications.


  • Grade 5 


A grade 5 bolt is distinguished by 3 radial lines and promises tensile strengths between 105,000 and 120,000 psi. They are most commonly found in automotive applications. 


  • Grade 8 


This sought-after grade 8 bolt can be distinguished by six raised dashes. Its medium-carbon alloy steel has been quenched and tempered, ultimately making it possible to achieve an impressive tensile strength of 150,000 psi, compared to a grade 2 bolt’s 64,000 psi. In other words, a grade 8 bolt is more than twice as strong as a grade 2 SAE American Grade bolt. You will often find grade 8 bolts in demanding applications, such as in automotive suspensions. 

Ultimately, the bolt that you select will depend on how strong it needs to be. The more demanding the application, the higher the grade that will be required. 

When it comes to SAE American Graded bolts, you can always turn to Marsh Fasteners for the finest selection and quality. Contact us now for more information. 


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