Puches/Chisels Down and Dirty hardening

[msropp2]

I'm lucky enough to have easy access to a relatively high carbon steel around 1% I believe. I'm going to be making punches and chisels and have been trying to understand the whole heat treating and annealing process but it seems to evade me. What is the best down and dirty way to somewhat harden the punches and chisels? Is it even worth it because they will be hot punches and chisels and wont they just lose the temper? I will continue to read and try to understand this process but thought  I would throw it out to you guys and see what you think. Here is a picture of the steel after power hammered into a rough tool shape. Th piece that was drawn out was from about a 5 inch section.

 

 

 

[stan]

The way I do it ,and I`m no expert, is if you not sure what your got try heating to critical temp( non magnetic) and quench in oil, then test for hardness with a file I use oil first because you forged item my crack in water if its oil quench .If its still solf repeat process and quench in water.When hard clean up surface to shiny, heat striking end say in the case of a punch until the colors begin to run for a punch you want straw to blue at the cutting edge, its all a bit trial and error.

Edited April 8, 2015 by stan

[arftist]

Assuming you have other stock to work with, test a sample as Stan described. A magnet on a wire is helpful. Non-magnetic is actually about 50 degrees under critical temp, so a little extra soaking time is appropriate. If it is .1% carbon, cooling it quickly in an oil bath (constantly swirling the piece around in the tank to ensure fresh cold oil is cooling the piece as quickly as possible) should result in a very hard surface upon which a file will skate.

One would then temper the hardness to a workable range depending upon the uses. Standard color charts do not really tell the whole story as different alloys require different temperatures to soften. 

Essentially you want to polish the surface to be tempered enough to show colors of oxidation. These colors are an indication of how hot the piece is. Say purple for example, which may or may not be too hot, resulting in a more springy tougher steel or a too hard (and therefore brittle) steel than desired for it's intended use. You will have to determine this by trial and error; that is the price of using unknown steel. 

So, after hardening (heating to above critical then quickly cooling) one would polish a section where the work would be done (polishing can be as simple as rubbing the work on a sharpening stone) then raise the temperature of the work until the temper color desired is running across the piece towards the edge. Then quickly cool in water. 

There is a lot more involved but until you swallow the basics it will be pointless to add to this. 

Annealing is accomplished by raising the temp of the work beyond the critical point, then cooling as slowly as possible. The cooling can be slowed in ashes, vermiculite, a cooling forge, a dying fire in a wood stove or by use of an additional very hot section of heavier steel to slow the cooling of the work piece. The metal is then as soft as it can be but could still be very hard depending upon the alloy.