A193 B7 and B-L7 bolt A193 B7 and B-L7 bolt Syahar1975 (Mechanical) (OP) 3 Mar 18 12:45 Dear experts, The drawing show A193 B7 bolt. The supplier gave me a bolt with B-L7 marking on the head. What is the difference and which is one is better. Syah RE: A193 B7 and B-L7 bolt SnTMan (Mechanical) 3 Mar 18 14:06 Syahar1975, making a guess here but, I'd say the bolt is dual-certified SA-193 B7 & SA-320 L7. Both the same nominal composition, SA-320 is impact tested. Depending on your Code of Construction, SA-193 B7 may have a higher max temperature limit. There may be other differences. You would likely need to confirm the dual certification, review the two specifications, your Code of Construction, if any, and assure yourself the bolting is suitable for your application. Regards, Mike The problem with sloppy work is that the supply FAR EXCEEDS the demand RE: A193 B7 and B-L7 bolt DSB123 (Mechanical) 5 Mar 18 14:06 Syahar1975, As an engineer you should compare the actual material/chemical properties of the actual bolt and check to see if it meets your criteria instead of asking others to do your job. RE: A193 B7 and B-L7 bolt Screwman1 (Mechanical) 5 Mar 18 17:13 The dual certified bolt has been tested to meet the requirements of both the B7 and L7 specifications. It isn't that one is 'better' than the other, just that it has been tested to meet both specs. If you need parts that meet both specs in the same application, go for the dual certified, if you don't need both specs, then just get one or the other certifications.