Oxy Acetylene cutting

Date 03-02-2014 06:27

The Oxy-fuel cutting process is inhibited in the action of rapid oxidation due to the chrome, carbon, and alloys present in the material. The reason it isn't recommended aside from the resulting poor quality of cut, is changes to metallurgical properties in the resulting heat affected zone.

But if your going to do it anyways, slightly oxidizing flame, adjust your cutting pressures to ensure a clear visible cutting stream, and feed a sacrificing low carbon steel rod into the stream to support a cutting/rapid oxidation action. You can cut it, but as they say, it just isn't recommended.

By Superflux (****)

Date 03-02-2014 08:31

"it just isn't recommended"
It is not a very attractive looking cut either.
Salvage and scrapyard work is where it's best used.

By CWI7611 (**)

Date 06-20-2014 14:20

What I always heard was that there wasn't enough carbon in the stainless to ignite and sustain the cut.

By aevald

Date 06-20-2014 14:46

Plasma56 included the key words: "it has to be capable of rapid oxidation", stainless steel doesn't possess this characteristic. Best regards, Allan

By 803056

Date 06-26-2014 02:44

Sorry friend, it has nothing to do with the carbon. If carbon was the key to cutting, cast iron would be a snap.

It is the iron that is oxidized by the cutting process. The reaction is exothermic meaning it produces more heat than it consumes. The preheat can be turned off when cutting thick sections once the cut has been initiated.

Stainless can be cut a couple of different ways. One is to use a special torch that injects a flux into the cutting stream to prevent the oxidation of the chrome. The other is to use a "waster plate" laid on top of the stainless plate being cut. The cut is initiated on the carbon steel plate and carried through the stainless plate. The maximum thickness of stainless is about 3/8 inch (from what I've read).

As mentioned by several responders, the quality of the cut may not be what is required.

Best regards - Al

By CWI7611 (**)

Date 06-27-2014 17:57

Yep, you're right, it is the steel that has to oxidize. I kept thinking carbon but knew it had to be the iron that continued the oxidized cut. When I had a steady arm and hand, I used to shut off the acetylene after the cut was started and just cut with the oxygen. Great party trick on the jobsite.

By SCOTTN

Date 07-01-2014 11:51

Agreed. Metals that can be oxidized, such as steel, can be effectively cut with a cutting torch. Other metals, such as aluminum and stainless steel don't oxidize, or rust, so they can't be cut with a torch even though an oxyfuel torch gets hot enough to melt these metals.

By 803056

Date 07-03-2014 16:52

See, this where we get confused with terminology. It isn't that chrome doesn't oxidize, it just that it oxidizes too easily. The passivity of austenitic and other grades of stainless steels is the phenomena that provides the resistance to "further" oxidation once the surface of the stainless steel has been exposes to oxygen (from the air or other source). The tenacious layer of oxidized chrome prevents further oxidation, thus the cutting action quickly ceases.

Best regards - Al

By ssbn727 (*****)

Date 07-04-2014 08:47

Correctamundo Al!