tig welding

[newton]

do you use dcen (tourch negative)straight polarity when welding stainless steel?

 

[Drains]

Always DCEN for TIG newton, regardless of material, otherwise you'll burn out the tungsten. Unless you're doing AC tig, of course, or DC Aluminium with a BIG tungsten.

 

[runnach]

Em em em, any improvement on touchdoon king Si?

 

[Drains]

Em em em, any improvement on touchdoon king Si?

Yes Terry, massive improvement thank you. I like the title though. Got to be top at something

 

[runnach]

Good stuff mate and, I agree title does have a certain coolness to it!

 

[Robotstar5]

Here's me thinking you had taken up American football Simon !

 

[Drains]

Here's me thinking you had taken up American football Simon !

Hut Hut! Aye, right.

Such days (if they were ever there) are long gone. Our neighbour plays American Football, and he's a grumpy b'stard.

How's sunny Brum then? I see they've knocked down Southalls in Ward End!

(sorry if this has gone off topic a bit Mods. I think the original question has been answered. Is it the beginning of a slippery slope though?)

 

[newton]

Always DCEN for TIG newton, regardless of material, otherwise you'll burn out the tungsten. Unless you're doing AC tig, of course, or DC Aluminium with a BIG tungsten.

thanks very much for your reply,can you actully dc alloy with big tungsten?i thought you had to have a ac machine,i have a oerlikon citig 1700 dc

 

[LeeW]

From what I have read, welding AL on DC with electrode positive would result in bad penetration as most of the heat will go into the tungsten.

 

[newton]

From what I have read, welding AL on DC with electrode positive would result in bad penetration as most of the heat will go into the tungsten.

so it carnt be done then?

 

[Sid]

About 2/3 of the heat of an arc goes to the +ve side, this is why you normally have the torch -ve. You could weld with a +ve torch, but you have to bear in mind that what you're welding will not be getting much of the heat, and that the tungsten will need to be suitably big to cope with the heat.

The reason you use AC on aluminium, is that it needs the torch to be +ve for part of the time to clean the weld pool, you do not need to do this on steel. AC cleans the weld without overheating the torch.

The idea of using a big tungsten and DCEP would work I guess (never tried) but you may be restricted to very light guage.

 

[newton]

About 2/3 of the heat of an arc goes to the +ve side, this is why you normally have the torch -ve. You could weld with a +ve torch, but you have to bear in mind that what you're welding will not be getting much of the heat, and that the tungsten will need to be suitably big to cope with the heat.

The reason you use AC on aluminium, is that it needs the torch to be +ve for part of the time to clean the weld pool, you do not need to do this on steel. AC cleans the weld without overheating the torch.

The idea of using a big tungsten and DCEP would work I guess (never tried) but you may be restricted to very light guage.

cheers for your reply