Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Technical Discussions / Stress Relief
- - By Milton Gravitt (***) Date 05-16-2008 22:40
We are GTAW welding .125 4130 Steel plates corner to corner with a 310 SS rod we preheat at 400° after welding it goes out to be stress relief at or between 750° and 800°my question is well it get hot enough to be distorted. When it gets back it gets more welding and stress relief I think about two more times.
Parent - - By DaveBoyer (*****) Date 05-17-2008 03:16
   I would expect it to move around "some". Dependingon how big the parts are and what sort of tolerances You are trying to hold it may or may not be a problem.

   This reminds Me of a Frank & Ernest comic. They are standing by a large '60s style computer- an entire wall covered with buttons, lights & reel to reel magnetic tape recorder/players. One of them has the printout in His hand. It says "MAYBE".
Parent - - By Milton Gravitt (***) Date 05-17-2008 14:36
The parts aren't that big you can hold one of them in your hand the tolerances are +0, -.020 on the first part. I guess it will be a trial and error on the first article.
            Thanks
                Thats a (maybe)or it (Might)
Parent - - By MDG Custom Weld (***) Date 05-21-2008 14:34
Milton,
We weld many details like you describe and are required to hold +/- .001 on some things.  We do experience some "change" in dimensions that require the part to be final machined or ground after treating.  Your use of preheat is the best way to control the movement.  Depending on your joint restraint and design we don't see movement much more that .007-.010 total.
Parent - - By Milton Gravitt (***) Date 05-21-2008 16:37
I don't think we're going to use a restraint when they have them stress relieved but if they stay with in .007-.010 they wiil be in tolerance. Thanks MDG Custom Weld I appreciate your help.
Parent - - By MDG Custom Weld (***) Date 05-21-2008 17:08
By joint restraint I meant the restraint that the welded part is under after welding.  Example is when a fixture and clamp is used to hold a part for welding to prevent the part from moving during the welding process.  Once that part is welded and it is removed from the fixture or unclamped, the joint has been restrained and heating it up as with heat treat will help the part relax, allowing it to move.  Pre-heat makes a big difference and you will be fine.  I think there is another post about distortion control in the "Tricks of the Trade" section that might also have some pointers for you.
Parent - - By Milton Gravitt (***) Date 05-22-2008 00:03
Thats what we are doing we have it restraint during the welding process.
                    Thanks because it made me relax a little.
         
                                                Milton Gravitt
Parent - - By Tommyjoking (****) Date 05-22-2008 08:46
nice post....It should not move much especially if your materials are preheated, as MDG states.  4130 goes soft with preheat pretty quick and reliable.   We have a distortion problem with some chromed 4130....the chroming process causes more distortion then the heat treatment apparently.   We have a secondary HT in place now which has made things better.   4130 is pretty springy until you heat it up...it draws a lot during welding.    We over-correct drawing issues to a specified tension now to allow for the plating and normalizing.  It is manageable to pretty tight tolerances.....but you just got to do it with the structures your working with to get it down....and have the the guys with the furnaces and plating tanks on the same page.

On a personal note I have developed a hate-hate relationship with this material in Gtaw welding.  But it is what it is.

Best regards
Tommy
Parent - - By Milton Gravitt (***) Date 11-13-2008 02:15
I know it has taken a long time to get back to everyone on this subject. This is what is going on now we built 3 right hand & 3 left hand weldments and sent them to stress relief they came back, we had to do some machining & some straighten, but they really hadn't change that much like Tommy said. They where sent to an outside sourse to be MT and they all passed. That was a stress relief on me. I would like to say thanks to everybody that helped on this.
                           
                                               MG


Parent - - By CWI555 (*****) Date 12-29-2008 16:06
I didnt catch this post originally, and it's probably a day late and a dollar short, but didn't you say it was welded with 310 stainless? I am curious how that was "MT'd" ?
Parent - By hogan (****) Date 12-29-2008 17:08
good catch
Parent - By Milton Gravitt (***) Date 12-29-2008 17:20
I see what you're saying about the SS 310 rod and I'm glade you brought this up, but I think it was on the print to do this type of testing. I go back to work a week from this Monday and I will make sure. It might be that the base material is 4130 steel. Hey thanks for getting my brain to think again.
 
                        MG
Parent - - By Milton Gravitt (***) Date 01-05-2009 15:21
  CWI555
I checked on this and I couldn't find it on the print but it is listed on the route sheet to go to MT.

                                MG

                                         
Parent - - By CWI555 (*****) Date 01-06-2009 15:08
Thats something I would be questioning as a typo.
Parent - - By Milton Gravitt (***) Date 01-10-2009 20:30
    CWI555 Sorry it has taking such a long time to get back to you, but I contacted the out side source that did the MT on this job and he assured me that it could be done. He went in to details on how he accomplish this job but it would be hard for me to try to explain it.

                    MG
Parent - By CWI555 (*****) Date 01-12-2009 13:48
Thats alright. I've followed it up myself. If they are trying to justify MT on a stainless component, I believe there is a lot of room for question.
Parent - - By sunn625 (*) Date 12-26-2008 01:25 Edited 12-26-2008 01:30
stress relief by vibration, replace the heating furnace.

Treatment effect of vibration stress relief is on a par with that heating furnace;Energy saving, emission reduction

My email:sunnn@semboo.com
Parent - By Milton Gravitt (***) Date 12-26-2008 02:32
It was called out on the print to be stress relief by heat treatment.
                          MG
Parent - By hogan (****) Date 12-29-2008 15:31
sunn625,
Except when not allowed by code
Up Topic Welding Industry / Technical Discussions / Stress Relief

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill