Machine heat treated metal

[abunaitoo]

I was cutting down the back of a Lee trimmer cutter.
It's hardened, so I heated it up to red wth a torch.
The cutter end was in a pan of water to keep it hard.
Let it air cool.
It still was hard.
Had to grind off the surface, then machine it.
How would I anneal (?) the metal to make it softer????

[bangerjim]

True HSS steel will not get soft if you heat it. Air hardening or oil hardening tool steel stock that was originally hardened by quenching WILL get soft.

bangerjim

[M-Tecs]

True HSS steel will not get soft if you heat it.

I use to anneal it frequently. It just needs a slower cool down.

http://www.highspeedsteel.com/HeatTreating.php

http://www.buffaloprecision.com/data_sheets/dsm2hs.htm

"Anneal: Heat to 1600° F, soak thoroughly at heat. Furnace cool 25° F per hour to 900° F, air cool to room temperature. Approximate annealed hardness 241 Maximum Brinell."

[country gent]

To anneal steel it has to soak and cool at temperature. Hardness required or wanted will delgate the tmp and soak times . While it will soften it dosnt get back to the original softness. Sometimes it just easier to use a sharp carbide cutter and turn it.. We used to cut snap ring grooves in bearing races with carbide cutter and ran the 2" race around 2000 rpm. Was a ball of sparks and fire but it did cut the groove in.

[bangerjim]

It might, but who has all that time to mess with it!!!!!!! And most on here do not have the ovens or temp equipment to attempt it. I have the equipment and have done it, but did not want to "tempt" people to try it with a propane torch.

That is why you can grind on a piece of HSS lathe cutter stock and it will not soften, just throw out dark red little balls of hot metal, not sparks!



banger

[R.M.]

Maybe it was case-hardened?????

[dikman]

Not sure if this will work with HSS, but "ordinary" hardened steel can be annealed by heating to the critical temperature and then burying in a bucket of ash. It gives a very slow cooling to the steel.

[oldred]

As some have suggested it probably was cooled too quickly, I have a pile of new obsolete farm mower blades 5/8" thick that I anneal to use for metal stock (hey they were free! :-P) re-hardening after cutting to the shape needed. I found these had to be cooled VERY slowly and even the burying in ashes trick did not work, sometimes if the equipment to properly do this is not available it becomes impractical to do. Before I built my oven I did manage to soften a couple of these things by keeping them hot with my torch and allowing the temperature to be reduced in increments but this a very crude way of doing it that didn't always result even hardness.

[abunaitoo]

It's probably just surface hardened. Once I broke through the surface, it cut nicely.
I don't want any heat to get to the cutting half of the tool, so oven is not the answer.
It's not a big deal. I was just wondering.