gas cutting stainless

[Lawnmowerboy]

Hi all, Next week at work i've been asked to cut 6 x 450mm circles out of 12mm stainless, would plasma be the easiest option or gas cut, both machines have a torch holder to make it easier to do circles

 

[Morris]

Plasma is the only option, gas cutting is nigh on impossible with S.S.
As an apprentice in the early '70's I was told of a method using iron filings injected into the cutting stream but never saw it done. In any case plasma cutting rendered it pointless.

 

[Welderpaul]

You won't cut stainless with gas. Use the plasma with the circle cutting attachment, with a steady hand, and the machine set up right it will make a nice job.

 

[Lawnmowerboy]

Ok, thanks. The Machine is a 45a Hypertherm, I'll try and get some pics when I do it.

 

[madkayaker]

Why does SS not gas cut?

 

[Lawnmowerboy]

I'm guessing it's something to do with it's chromium content which does not "burn" like ferrous metal. i heard once you have got the cut going and the metal burning then you can turn the fuel gas off.

 

[hotrodder]

Because stainless is resistant to oxidation ...

With steel the flame preheats things to a point where the oxy jet starts an exothermic reaction and away you go. Stainless, ally etc form refactory oxides which have a higher melting point i.e. you end up melting things before the reaction starts

 

[madkayaker]

Makes sence when you put it like that! It's probity the same reason why cutting thin stuff with gas is a pain

 

[Lawnmowerboy]

Yeah, you melt it rather than cutting it on anything less than about 2/1.5mm