Soften a hidden tang?

J

jawilder

Joined
Jun 27, 2006
Messages
2,331
I usually only quench the blade and leave my hidden tang soft but this one got hard. My drill bits won't touch it and I have tried several times to soften it with a torch but must not be doing something right.

I have wrapped a wet rag around the blade and bring the tang up to glowing orange, darn near melting but when it cools it is still hard. I tried putting it in pearlite to cool it off but that didn't seem to help.

My next step is to get a small enough carbite bit (which I need anyways) but would like to know what I am doing wrong.

Thanks,
Jason
 
You're bringing it up way too hot and getting some air-hardening.
Turn the lights off in the room.
Just bring the tang up to a dull red where you can just barely see it.
Let it cool completely.
Do it again once or twice - preferable twice.
It should drill like butter.
 
I've been wrestling with 1080 and among other things I learned about "lamelar pearlite"

Sunshadow told me the following;
Quote: "What it sounds like to me is that you have lamelar pearlite (no not the expanded mica that you get at the garden store that you are using to slow cool your steel, but little flat carbides that have precipitated out of your steel because you are cooling it too slowly that will ruin hacksaw blades and drill bits)

I think the key to fixing your problem is that you need to do a speroidize anneal. Instead of heating up to Austentizing temp and then cooling extremely slowly which will precipitate large sheets of impenetrable carbides, you need to heat your steel up to just subcritical, cool it quickly, heat it a little less, cool it quickly, and cycle it a few more times, each time heating it to a lower temperature. That will break up the carbides and ball up the remnants so that they move out of the way of cutting tools instead of just destroying them."

Good luck.

- Paul Meske
 
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