Welding 304 Stainless .065 Tube

MadisonRods · Tue Oct 18, 2016 2:24 pm

As the title describes, I am welding 304 Stainless .065 tubing with back purge. My question is how to control the distortion (low areas) on each side of the weld. This particular customer requests that I sand the weld smooth for polishing. That creates problems with the low areas.
Thanks in advance for any help.

LtBadd · Tue Oct 18, 2016 3:46 pm

Welcome to the forums
Can you provide more info? Such as are you using filler and what is the amperage. Honestly you shouldn't be getting "low" areas, so it sounds as though your not using filler. Post a photo if possible

exnailpounder · Tue Oct 18, 2016 6:33 pm

I just did some .065 SS tubing and I pulsed it but your post is a bit confusing...can you elaborate?

Rick_H · Tue Oct 18, 2016 9:24 pm

I'll assume no filler, full pen since you are back purging. I use 45-48amps straight, 1/16" tung, large cup and gas lens. I also pulse 2.5pps 50% on 50% 55-58amps 1/16" ting gas lens large cup.

Here one polished with an ultra fine scotchbrite belt

MadisonRods · Thu Oct 20, 2016 1:21 pm

Thanks for the help. I will get a couple of pictures up to help describe my issues.

MadisonRods · Thu Oct 20, 2016 11:21 pm

This is pretty typical of what I am getting. Usually one side will sand down fine. Filler is 308/035 @ 40 amps

Oscar · Fri Oct 21, 2016 8:26 pm

I see what's going on. Mainly because I'm guilty of making the same mistakes

You're not lining up the tubes axially. One tube is off to one side by a few thousandths. It's not distortion that is causing low areas---the tube itself is low to begin with, on that side.. I've drawn a red line to illustrate:

The solution? Either continue grinding that area carefully until it appears properly blended. The right thing would be to get a better fit-up so they are dead-on axially.

Rick_H · Sat Oct 22, 2016 2:52 pm

I see the same thing as Oscar, alignment and fit up is key. Is what I showed above not acceptable? If not you could sand that area down and feather it out, I have a specific machine that wraps belts around tube, makes life easier.

Rick_H · Thu Nov 03, 2016 1:05 pm

What did you end doing?

MadisonRods · Mon Nov 07, 2016 3:37 pm

Better alignment seems to be my problem. I have started to take a considerable amount of time up front making sure my fitment is the best it can be. I would say 90-95% of my problems have disappeared. Thanks to everybody that took the time to reply to my post!

dave powelson · Tue Nov 08, 2016 11:33 pm

MadisonRods wrote:Better alignment seems to be my problem. I have started to take a considerable amount of time up front making sure my fitment is the best it can be. I would say 90-95% of my problems have disappeared. Thanks to everybody that took the time to reply to my post!

Fade out to stop those craters, which are crack generators and can be tight leakers.