Varies, I can not give you a good answer because it depends on who is cutting it. If done by hand may be inconsistant with different skill level, if done by CNC same reason by the programmer or operator, plus on corners there is more heat put into it due to dwell times.

also the type of heat sink you could be using if any at all.

p911

If your plasma cutter is correctly sized for the material the cut will be fast enough that there is little to no losses in the tempering.

Just look at the heat coloring band next to the outgoing side of the cut. If it is very narrow then very little excess heat was transfered to the metal and that heat colored area is the only part that may have had any degree of change in its tempering.

If the cut was good and the heat color band is usually not much wider than the cut itself.

However if it was a slow cut made by a machine being ran at it limit the change in tempering may be about the same or worse than a cut made by an Oxy torch or abrasive cutting blade.

Should of asked how thick

Limited if machine is properly sized and varies depending on pre-heat temperature of material immediate to the cutting.

I have worked with plasma cut 5/8" a-36. It seems not the cutting but the welding afterwards warranted the heat treating.

Ron, the answer is yes (without beating around the bush, like the other specialists around here). There is always going to be an affected zone, which can be of minimum a few thousands, I suspect larger than that. In general, the affected zone will be hard and brittle (like as quenched, or with a mixed microstructure), and it requires a temper after cutting. Same with laser, EDM, EB, flame or any high temperature cutting devices.

Titi-the-rabbit

"Ron, the answer is yes (without beating around the bush, like the other specialists around here)."

Well, specialist, do you know what he is going to do with the piece he is plasma cutting? There's not enough information given to render a proper answer.

I don't believe he's building airplanes. But, who knows? Can you predict what his objective is based on the question?

Dear lyn, in general you're a keen person. But this time... His question was, let me read it to you: "To what extent is temper affected by plasma cutting? Is it enough to warrant additional heat treatment?" I think the question was pretty straight forward, and the answer as well. He can choose what to do with the answer based on his application. Now, my answer was yes, (I should have said "for steel") it is always affected, at least a few thousands (which is the part he really needed), and it needs a temper to correct. How is your answer going to change based on the application, please explain? If he doesn't build airplanes is plasma not going to affect the temper? That, my friend is beating around the bush. Get rid of your retired automotive engineer attitude.

Titi

You are correct. The question was answered properly. I derailed the thread. I'll butt out.

I'll flog myself at 9:00AM if anyone wants to watch.

Thinks he's s specialist....evidently yes.....because he's basically a self proclaimed specialist.

Idiot does not realize that nothing is prefect. but then again it's a guest.

Sure there will be coloring but take into account thickness of the material, type, operator mood/health, machine maintenance. are all factors.

Phoenix, please do not call me an idiot. I was ironic and I apologize, but from that to the name you gave me it's a long way. Please control your vocabulary. The whole thing was a matter of interpretation. It is my fault, I started this, but again, there is no need for insults as such. And I think I have some idea about metals since I have a PhD in Materials Science and Engineering and a bit of experience - maybe that qualifies me somewhere in the neighborhood of a "specialist".

Titi-the-rabbit

I apoligize for calling you an idiot, and appreciate you coming forward from a guest's position. And yes that would qualify you as a specialist.

p911

My question was general. Although I can think of hundreds of uses for a CNC plasma cutting machine, My concern was for any application that requires the finished parts to have the correct temper. An example would be parts cut from 1/8" thick steel and used to create a tool that has stresses on it. Something like a pair of pliers made of laminated 1/8" steel plates. I apoligize for not giving more information and causing a "rift" amongst the faithful.

Sorry.

Your question was clear, as written. I went off on a tangent and should have been quite.

Ron, apologies from all.

And since it is a general question, heat treated would normally come after the cut.

I had worked at a company that normally had 3-4" material to be plasma cut, the machinist didn't care for it because the quality (of the cut) varied.

As far as stress, I had cut plasma and waterjet, and on 3/8" plate the stress there as you were cutting would lift the material into the head, this would be the quality from the mill whether the plate was normalized.

As far cutting material that was tempered, the control could not be there and to bring back the desired characteristic after the cut it would have to be heat treated again.

p911