Welding 443 stainless to 409 stainless

Date 07-21-2010 00:34

Need to weld 443 S.S to 409 S.S.. The Mat. thickness is 1.5-2mm, and it's going to be a corner joint welded in the horizontal position. We are using 308LSi filler, and the shielding gas is a tri-mix Arg, He, CO2 at a mixture of 65% Ar, 33% He, 2% CO2. The App. is for Cat. Converters so the thermal stresses are what drive the Mat. choices, and the fact that is what the customer is supplying. We have experienced failure right down the center of the weld. There in lies my question. Are we using the right Filler and gas combination? Are there other factors to consider, and what other information do I need to post for replies?

By 803056

Date 07-25-2010 19:27

Were the cracks noticed while being fabricated or after being in service?

Best regard - Al

By Rick Hoople (*)

Date 07-27-2010 23:31

Hey Al,
It was after it was in service. I find out now that they have changed the joint design, we'll see how that works. Tnx for the reply.

Rick

By dholdren Date 07-28-2010 14:50

Rick, you might have better luck with an austenitic filler metal with higher ferrite content such as a 309 or 312, but not certain what will happen at elevated temperatures. They also make a number of matching filler metals for the 409, but not certain what will happen with the higher carbon content of the 443. There are several nickel-based filler metals that could fit the bill as well.

Good luck.

Dick Holdren