Proper Bolt Tension

Only structural steel bolts have an associated tension recommendation. The desired tension on a structural bolt is achieved by using a calibrated torque wrench and a Skidmore-Wilhelm load indicating device to tighten the nut with torque indicated by a verified bolt torque chart. ASTM does not have any recommendations in place for the proper tension on general-use bolt specifications such as ASTM A193, A307, A320, A354, A449, F593, or F1554 etc. There is a wide array of different configurations and applications for bolts made to these specifications, so recommending a proper tension is impossible. ASTM A325 and A490 cover a very specific type of bolt used in structural steel connections, so they are the only specifications that have an associated tension. Each of the general configuration/application bolt specifications will have requirements in place for tensile strength, yield strength, elongation (%), and reduction of area (%). Learn more about those terms in our glossary, and more about the tension/torque relationship from this FAQ. Portland Bolt certifies bolts to these ASTM specifications and more. Please contact one of our team members with any further questions or if you would like a quote on your custom bolt order.