TIG Weld 316L to Inco 625?

Date 07-27-2009 19:25

I have some 316L tubing that has a wall thickness of 0.080" and a piece of Inco 625 tubing that has a slightly larger diamter, but the wall thickness is about 0.049. The 625 tubing slides over the 316L tube and I'm contemplating whether or not a fillet weld to join these 2 sections is a good idea.

On a side note, what kind of complications arise when welding 316L? I want to make a 4.5 ft long section of tubing out of 0.080" wall. I'm assuming that rolling a 4.5 ft long section and then welding it longitudinally would not be a problem, but what kind of variables should I take into consideration?...distortion, heat input, purging, etc?

Thanks

By OBEWAN

Date 07-27-2009 19:47

We make lots of piloting tube fillet welds for jet engine igniters and we don't have any problems with them.

We usually weld 430 stainless to an Inconel or Hasetlloy. Sometimes we even do it with the "forbidden" 416's. It would probably be easier with a 300 series.

Most of them are autogenous too, but I think the average wall thickness is only about .035.

If you try it without filler and have cracking issues then you could do it with some 312 filler.

I am not sure what to say about making your own tube. That is best left to a tube mill welding rig I would think.