Creating welded bolt to replace forged bolt
Creating welded bolt to replace forged bolt
(OP)
I am currently reviving an older bolt design which uses an EDT150 or 4140 QT stud that is threaded at both ends and is going to be welded to a nut on one of those ends. This in turn will create a bolt. We switched over to solid forged bolts a few months ago and we've been having problems with the heads popping off after preloading the bolts to the proper torque specification. The older welded bolts performed with much more longevity and had much lower instances of head failure. The only thing is that the welded style bolts were never heat treated after welding. The end of the stud that has the welded nut on it is chamfered to allow for a bevel weld. Any thoughts on normalizing and heat treatment after weld? Any thoughts/comments would be helpful. Thanks.





RE: Creating welded bolt to replace forged bolt
I read through your post and must have missed something. Your original style threaded stud/nut welded was used as a bolt. You had no reported problems. Now you have switched to a forged bolt and still weld the nut on the other end, correct? You refer back to a welded nut/stud and not having any problems, yet you are asking for post weld heat treatment recommendations for what - the old style threaded rod design or the new forged bolt design?
RE: Creating welded bolt to replace forged bolt
RE: Creating welded bolt to replace forged bolt
I would suggest a post weld heat treatment for the 4140, the only problem is I do not know the strength level of the stud. If you can determine the tempering temperature used in the original heat treatment of the stud, stay 50 deg F below this temperature for your PWHT. Use 1 hr/inch of thickness as a guide for PWHT.
RE: Creating welded bolt to replace forged bolt
Thanks a bunch, i really appreciate your input.