NO requirement of preheating before welding s.s.

[hvdesai1284]

DEAR SIR,
I WANT TO KNOW WHY PREHEATING IS NOT REQUIRED FOR WELDING S.S.MATERIALS?

 

[21121956]

Hello everybody:

That statement is not correct at all. When it comes to the point of the welding preheating, the question of whether a stainless steel should be preheated for welding, one comes to know that in general, for austenitic stainless steel preheating is not helpful because no structural changes occur, such as martensite formation in the weld or in the heat affected zones.

In some cases, preheating could be harmful in causing increased carbide precipitation (weakening the condition of stainless) or induce greater warpage.

It cannot be say the same for martensitic and ferritic stainless steels, they need to be preheated prior the welding.

El que no puede andar, se sienta.

 

[metengr]

Because for austenitic stainless steel grades, they do not harden by heat either from welding or heat treatment. For hardenable grades of stainless steel, like martensitic and ferritic grades, preheat is necessary to reduce the rate of cooling in the base material and weld region to avoid hardening.