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need advice about thick to thin

Posted: Thu May 18, 2017 2:48 pm
by dutchwelder
Hello,

Need some help,
For a job i need to weld 10mm stainless bar to 1,5mm thick stainless tube.

I struggele a littlebit with it.

I use a 160 dc pulse tigmachine.

Can someone give me some advise about the settings?

Re: need advice about thick to thin

Posted: Sat May 20, 2017 12:28 pm
by electrode
dutchwelder wrote:Hello,

Need some help,
For a job i need to weld 10mm stainless bar to 1,5mm thick stainless tube.

I struggele a littlebit with it.

I use a 160 dc pulse tigmachine.

Can someone give me some advise about the settings?
A few questions. Maybe pics would help too. What is the intended use for the pieces you are trying to join? The best advice for doing what you are trying to do is to favor the thick piece and add filler to connect the thin piece. Better to see so we understand what you are using this for. As far as settings you will most likely want to do a few tests to see if you can use all 160 amps or not, or if you even need to based on what the end result needs as far as strength.

Re: need advice about thick to thin

Posted: Sat May 20, 2017 2:03 pm
by dutchwelder
this is the part i'm talking about.
the tube pieces are only 15mm long so the heat wil melt te top of the tube's
when i use less amp the 10mm rod doesnt melt. :cry:

Re: need advice about thick to thin

Posted: Sat May 20, 2017 3:26 pm
by Oscar
How well have the practice pieces gone? PIctures? You are practicing on parts that are not the actual project, right?

Re: need advice about thick to thin

Posted: Mon May 22, 2017 11:42 am
by dutchwelder
here are some pictures of a practice pieces, as you may see the edges are +- 0.5 mm thick.

the machine setting i have used
75 amps
1 pps
pulse width 30
background 30 amps

when i use less amps i dont get a melt pool on the 10mm rod, at least not in a reasonable time so i putt to much heat in the material

Re: need advice about thick to thin

Posted: Mon May 22, 2017 2:27 pm
by LtBadd
dutchwelder wrote:here are some pictures of a practice pieces, as you may see the edges are +- 0.5 mm thick.

the machine setting i have used
75 amps
1 pps
pulse width 30
background 30 amps

when i use less amps i dont get a melt pool on the 10mm rod, at least not in a reasonable time so i putt to much heat in the material
I would weld the top first while the part is at room temp, favor the round bar (torch angle) and add filler on the tube side, once you start weld as fast as you can. Get this area done first (4 plcs) then go back and finish. Also is there a way to put a heat sink inside the tube?
20170522_163601.jpg
20170522_163601.jpg (38.73 KiB) Viewed 1404 times

Re: need advice about thick to thin

Posted: Mon May 22, 2017 2:41 pm
by electrode
That looks like some pretty big filler rod. What size is it? Also, sharpen your tungsten to a fine point to focus the arc and maintain a close arc too.

Re: need advice about thick to thin

Posted: Mon May 22, 2017 5:54 pm
by LtBadd
electrode wrote:That looks like some pretty big filler rod. What size is it? Also, sharpen your tungsten to a fine point to focus the arc and maintain a close arc too.
I'd be using .035" filler, you may be able to get away with .045" but you better be fast and tight. ;)

Re: need advice about thick to thin

Posted: Mon May 22, 2017 5:58 pm
by Rick_H
I like the idea of pressing in brass or alum heat sink, will also help if you get greedy and get through. I'd run no pulse, focus on the thick, thin filler and wash the weld down into the thin.

If done this on 316L tubing .065" to various thicknesses and it works very well. Could also preheat the bar a little. Is the end of he bar coped to fit the ends or are you also filling a gap?