ER 630 stainless

by Daren
(London ON CA)

I am welding with ER 630 stainless hard wire and am looking for a better gas than straight AR. I'm using Ar 98% o2 2% which seams to work well but I'm getting some cracking in the middle of the weld and at every stop (puddle). Any hints or tips would be greatly appreciated as well as weld parameters


the cracking might be coming from another reason than the gas type.

often on highly restrained joints like socket weld flanges , when a gap is not used, there is nowhere for the piece to move when the weld metal shrinks and it results in cracking.

if stress is not the reason in your case, then a thicker weld that is slightly convex might help.

thx for the post,


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Jun 11, 2014
Correction NEW
by: Sandman

Ok What I MEANT to say.

I meant if the weld pool is concave it is under tension and will split.

if it is convex it is under compression.

Thanks Sandman

Jun 10, 2014
Cracks NEW
by: Anonymous

Hello are you preheating the material first? How thick is it? I am welding 630 now it is heat treated and the coating on the bar is unbelievably hard to grind off by hand....

Oct 14, 2013
problems with cracks NEW
by: Anonymousjohn

I weld half in stainless racks for a heat treatment co. I use 0.045 flux core wire, these racks go in a oven @ more than 1000 degrees , the weld cracks after a few uses, need to know what i need to do to stop it.

Jul 29, 2013
weld cracking NEW
by: Sandman

Yes I agree
so preheating will help with all welding
Hydrogen embrittlement cna be a cause
but recently i found if you leave the weld concave when the weld pool shrinks it will be under tension if it is concave it will be under compression.

I hope this will help you

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