It is a must that you need to follow the WPS or Welding Procedure Specification before you proceed the welding. However, many things you have to consider, if this is new material you need to prepare mock up test, or if it is already have an experience but still appearance of distortion is there, somehow you have to check and re-mock up to correct the following:

1. Improper tack welding prior to full welding.

2. Improper bead sequence.

3. Improper set-up and fixturing.

4. Excessive weld size

thnkx sir..n more u can tell abt this distortion any books can i refer ..

An excellent book on the subject is "Ananysis of Welded Structures" by Koichi Masubuchi (Pergamon Press)

_{oops.. Isn't it Dr. Omer Blodgett?}

I don't know. You mean he welds and delivers babies?

Surely, NOT at the same time!!!!!!!!!!!

Sure, it's considered very green. The sound from the screams is converted into electricity with a moving coil microphone. The technique is often used in cities with high population density -- you find OBGYN clinics and weld shops side-by side.

Sequence, sequence, sequence.

Move the heat around and you get less distortion.

thanku sir

Distortion it self in welding is a warping of base metal or throwing of the set up material from alignment by the following means, Angular, Longitudinal, Transverse distortion during tacking and welding or after welding. And these can be corrected by applying the weld sequence methods or mechanical methods by using jigs, wedges etc.

Distortion it self in welding is a warping of base metal or throwing of the set up material from alignment by the following means, Angular, Longitudinal, Transverse distortion during tacking and welding or after welding. And these can be corrected by applying the weld sequence methods or mechanical methods by using jigs,fixtures, wedges etc.

All of the answers are correct. A good preheat will help too. Preheats help with the thermal shock and slow the cooling rate. it also expands the base metal somewhat so that when the molten weld metal cools its shrinkage more closely matches the weld metal.

a word of caution concerning the use of jigs:

jigs are great for initial alignment, and tacking the workpiece together,but a rigid jig left in place during welding will often result in very large internal stress and significant distortion.

it is best to tack a piece together in the proper alignment and then remove the jig to weld, then correct alignment after welding.

benbenben