How to Use the Stud Bolt Allowable Tensile Load Calculator
Stud bolts used in flange and piping connections carry sustained tensile load once tightened, so checking the allowable tensile load before use is basic to a safe connection. This calculator uses ASTM A193 grade values - the standard specification for alloy and stainless steel bolting for high-temperature service - along with bolt diameter to approximate the effective stress area and calculate both allowable and ultimate tensile load.
Effective stress area is approximated at about 75% of the nominal cross-sectional area to account for material lost to the threads. Allowable tensile load is based on the grade's minimum yield strength divided by a safety factor of 1.5, while ultimate tensile capacity is shown for reference so you can see the margin to actual fracture strength.
A safety factor of 1.5 is a common reference value for general piping and equipment bolting. If your project follows a code such as ASME B31.3 or an internal engineering standard requiring a different factor, apply that value instead. For critical connections, have the final bolting design verified by a licensed piping or mechanical engineer.
Frequently Asked Questions
The bolt's effective stress area is multiplied by the grade's minimum yield strength, then divided by a safety factor of 1.5. Stress area is approximated at about 75% of the nominal cross-sectional area to account for the threads.
1.5 is a common reference safety factor for general piping and equipment bolting. If your project follows a code such as ASME B31.3 or an internal design standard with a different required factor, use that value instead.