Tig Welding Carbon Steel 1

[Supatube]

Hello all,
I'm not sure if I am posting this under the correct forum but I am sure someone would know something about it.

Will it be possible to buttweld two carbon steel sheets together using tig welding process? Will it be necessary to make use of a filler material when doing so?

Alternatively, would it be better to make use of plasma welding for this?

thanks a lot!

 

[rd400guy]

Sure you can weld 2 sheets of mild steel using GTAW(TIG). More info would help...

What's the thickness of the sheets? Are both sheets the same thickness? What are the overall dimensions of the sheets? In other words, is it a long weld (in which case GMAW(MIG) might be better)? What is the grade of steel.

GTAW can weld mild steel easily, and it is possible up to about 1/2" thick, but this would require multiple passes, with bevels & filler rod (ER70S-2 filler would normally do). If the sheets are thin, 1/16" or less, and you get a good tight fit, you can butt weld with GTAW without filler and still get full penetration on a single pass. If you're a good welder, you could probably bump that up to 3/16" thickness without filler and a really tight fit.

There is a Welding, Bonding & Fastener engineering forum on this site (for future welding related posts).

 

[metengr]

TIG (GTAW) welding without filler metal can be performed for joining thin gage carbon steel material (1/8" or less in thickness). Make sure the square ends of the sheet are cleaned and butted together for welding. Welding without filler metal is called an autogenous weld.

 

[strokersix]

It will be helpful to back up the joint with shielding gas or copper sheet. This will keep oxygen away from the molten metal. Also, a copper sheet will support molten metal and help to prevent blowing a big hole in your material.

 

[arcer]

If you have the budget, and the justification, you may realize some advantages to a plasma setup. You didn't tell us how many feet of weld you have to make, and an automatic setup using either GTAW or PAW requires a substantial investment of time and $. While you could splice a few feet of plate together using GTAW without any fixturing, I would think that not to be the case with PAW, however if you're contemplating setting up to do a lot of this type of work, I'd suggest you look at both methods. One of the advantages with plasma is that you could butt the plates up with no gap and readily achieve full penetration, with higher travel rates than those typically possible using GTAW. In my experience, for high production runs, the fixturing is every bit as important as the welding equipment, so don't try to skimp there.

 

[Supatube]

Thanks for the reply's. I am in the erw tube making industry.

We have to make buttwelds when joining two steel strip coils. Currently they are using CO2 welding. But this has one big disadvantage, due to the fact that material is being added to the weld it has to be grinded down after every weld. This extra time required for the grind does cause some problems.

If by changing to tig or plasma welding it could be possible to eliminate the need for grinding it will be possible to save about (2 min minus the extra time it requires to make tig weld). This is not a lot of time by itself but could result in fewer downstream stoppages of the plant and have some major benefits.

The problem with the filler material or large weld bead is that it will damage the tube mill it passed through the mill ungrided.

Max strip thickness is about 6mm (0.23") and about 300mm (11.81") wide. Different grades of carbon steel is used on the machine.

I am going to do a test with tig welding tomorrow but I do not have plasma welde available at this stage.

What do you believe will give the cleanest and fastest weld? Can anyone foresee any problems with my theory of changing the welding process?

Thanks in advance.

 

[Ron]

For a weld of the thickness you are discussing, I think you will need filler metal for all except ERW and plasma. For GTAW (TIG) you will need filler metal. Also, I assume you need an automated process, not manual. Stick with ERW or Plasma for this.

 

[Supatube]

At this moment a manual system is being used, at this stage I dont mind if it remains that way.

ERW will be a little out of reach for this specific setup. I will definately have a look at plasma as well

thanks