Blade cutting with plasma cutter?

[DNS]

Will plasma cutting remove temper from carbon steel?

I'm planning on making some blade blanks and honestly don't know. I'm thinking not but maybe i need to invest in a laser temp gun?

 

[highorder]

It will affect the temper in a small zone around the cut. Are you not planing on hardening and tempering after shaping?

I've cut blanks out with a cutting torch, but of course I heat treated after that.

 

[hso]

If you're just cutting blanks it shouldn't be tempered anyway unless you're using some material already heat treated.

As pointed out, you'll have a small zone that the temper changes. That material will probably be ground away and you'll end up getting into tempered steel (and eating up grinder material) quickly.

 

[rcmodel]

I think any time you cut high-carbon steel by melting through it, you are going to burn some carbon out of the edges next to the cut.

Finish grinding the blank to final size should remove the part that got fried by the plasma.

But removing tempering hasn't got anything to do with it yet at that stage.

rc

 

[Jason_G]

As hso and rc said, if you are making blanks, the steel ought to be annealed anyway, so there is no temper or heat treat to ruin. That said, you will have a heat affected zone surrounding your cuts, and those could provide spots for warpage when you quench later, especially if those hot spots are asymmetrical.

If you use a torch or plasma cutter, cut your blank a little bigger than you need, and then grind down to the size you want, getting rid of that heat affected zone.

Now that's just what I would do, to each their own.


Good luck with it. Post some pics.

Jason

 

[Claymore1500]

Just a side note from a guy that has plenty of experience with plasma cutters.

Unless you are cutting 1/2 inch stock, you should be able to pick the blank up in your bare hands just seconds after the cut, there is VERY little heat transfer around the cut.

 

[Jason_G]

Unless you are cutting 1/2 inch stock, you should be able to pick the blank up in your bare hands just seconds after the cut, there is VERY little heat transfer around the cut.

Really? I've never used one, but I'd have never thought that. That's pretty cool (no pun intended, seriously).

Jason

 

[Claymore1500]

I used to do a lot of fabricating work in the truck shop I was working for, we used a plasma cutter to cut aluminum and steel, up to about 1/4 inch thick.

The machine generates a very hot electric arc, which is capable of melting that thickness in steel in about 1/2 of a second, the arc is constantly being hit with pressurized air, (as I recall we regulated the air pressure to about 60 p.s.i.), the air immediately blows the molten metal away, leaving a cut just about as wide as the line from a standard "Sharpie" marker, the air keeps the surrounding metal cool, in fact, you can cut sheet metal for automotive body work, without distorting the metal, it will burn the paint around the cut maybe 3/8 inch.

 

[Zeke/PA]

Usually the hot arc of the Plasma cut will draw Carbon from a steel workpiece to the area of the cut making that small area "super hard".
However , that small area is usually ground away and shouldn't affect your final product.