Straightening Welded Components

Well, well, well, heat up to the red and cold water? This will surelly cause some effect, but... I definitely doubt that you'll have some kind of straight shape as you mention. Not talking about the metalurgical structure that will remain after this "magic...". Definitely, does not work where you have to assure quality. And, if you does not need to, you doesn't need to be upset with the deformation too, so, just hammer it back...

Several methods of MINIMIZING distortion can be used. You'll never eliminate it at all, because in welded parts you will always have remanescent tensions in the order of the yeld strengh of the material. Solutions normally used are pre-heating the base material, parts clamping during weld and stress relieve still clamped in the shape, cold working (remember the "hammering"?), and controlling the weld process itself, reducing the size of the weld, alternating the weld sequence, making interrupted weld beads, using some low heating technology like electron beam, laser, or even changing your design to weld the part in a region that would not cause geometry problems if distorted.

Quite vague, but, if you give us some details about the weld geometry and how it's being welded, another idea could come up to me.

The welded items were T sections made using 1' wide 3/8" thick plates. There was a double fillet at the center of the flange plate. It got distorted at various places and this guy just looked it over carefully and I believe applied heat at certain locations w.r.t. the distortions so that when heated and cooled the resultant distortion would nullify the previous one. Is this any help?

If you have a lot of these brackets and you don't want to hammer a lot, because you already welded them (therefore it is too late to clamp them down). So I would suggest what I would have done if I were in your position. Build a simple jig and with the right leverage (some tube or pipe that fits over the 1' x 3/8'') supported at the distorted spot you just give it a little bend back, aim with your one eye over the straightness.

In the rail industry, it is common in principle to heat rails up to a predetermined temperature before re-surfacing by arc-welding, so that the influence of the welding technique has a minimum effect on local metallurgy. After welding the rails are heat-soaked for a period and then allowed to cool slowly. When cool, they can be ground back to an acceptable profile. The procedure selected is determined by the size and shape of the component rail, and its metallic composition.

A detailed discussion with an experienced metallurgist might reap dividends?

Straightening Welded Components

I do have witnessed this technique by experienced welders and it does reduce distortion to a great extend , though it may not fully eliminate it .It is quite unpredictable but is OK for rough structural works. This art full skill of welders needs to be experimentally studied and theoretically correlated to become a text book guide for the benefit of welders technology.

See "Distortion Control" and"Flame Straightening Technology", both by John P. Stewart.

Mr. Stewart, a french-canadian, is the "godfather" of using localized heating to minimize welding-related distortions.

Hi,

Please send me more details on this.........I am interested in procuring this book.

Mr. Stewart's contact information is 233 Dupras Avenue, La Salle, Quebec Canada H8R 3S4 Phone: 514-366-8410 Fax: 514-366-6358

Does vibratory stress relief help to control weld distortion? The marketing people for VSR have made claims of a dramatic improvement. We have have done some crude experiments which also showed improvements with VSR.