Elastic Bend, Cold Bend, Induction Bend, Elbows

Hello Fellows,

What process in cold bend, induction bend and elbows that relieves the axial stress developed during the bending process which is always present in elastic bend.

Warm Regards,

Typically, no particular action is taken to do so.

You inspect the end piece for deficiencies, and then test it accordingly.

From a stress analysis standpoint, this means that you should increase the OD and decrease the WT per the bending limits.

Over time, the stresses induced through bending should abate as a function of temperature and material. Normalization could be used to speed the process up, and may be warranted in critical applications.

However, I qualify the previous statements as not being a metallurgist.

I'll also note that for critical applications, you'll often see significant padding of thickness as a safety margin of error.