Bad batch of steel?

B

blaksdc

Joined
Oct 10, 2019
Messages
12
So a few years ago I bought a billet of steel and prepared some knives from it. I sent one out to HT but came back at 32/33 HRC, and they said it was not the steel I declared/couldn't harden (it was 1070 steel), so I put the other pieces I prepared away and forgot about them. Yesterday I found these 2 or 3 knives on a shelf of the garage and thought about what could I do with them.
Is it possible that, since billets are made (I think) by pouring, the steel was faulty on only a spot, where it was tested (wrong mixing or something)?
The question is, should I try to HT it anyway (at home now that I can) and then maybe test it by batoning/rope cutting and such?
My worries would be that the RC could vary through the blade or something, something that I didn't worry about too much until now.
 
There was a recent thread that spoke (in part) about the condition of steel prior to HT ... and that some steels come from some manufacturers not ready to heat treat ... the key being normalizing (appropriate to the steel) prior to HT. JT should have something to say about this - I expect him to chime in here.

If that is the case ... then the "good" news is that both your previous knives and the left over billets should be salvagable - just need to be processed appropriately to make them "HT-ready"
 
Cushing H. said:
There was a recent thread that spoke (in part) about the condition of steel prior to HT ... and that some steels come from some manufacturers not ready to heat treat ... the key being normalizing (appropriate to the steel) prior to HT. JT should have something to say about this - I expect him to chime in here.

If that is the case ... then the "good" news is that both your previous knives and the left over billets should be salvagable - just need to be processed appropriately to make them "HT-ready"
Click to expand...

Cool! I'm gonna search the thread.
It might actually be possible that it was not normalized correctly. I'll try to normalize a few times, the first one at 1600F or so, to let the components of the alloy soak throughly and normalize in all of the piece. Honestly I don't remember if I normalized it before sending it out, or if they did it, because it was quite a while ago, but that might be it. Thanks again!
 
John mc c said:
Where did you buy the steel?
Click to expand...
Italian knifemaking supplies site (lccoltelleria.it). It's used by most italians knifemakers, and other billets of the same steel but different thicknessess never gave me problems (it was the first time i bought 1/4 inch thickness, the one i sent to the same HT company were from 1/8 or so).
 
Some steels need a very fast quench at 1/4" thick to get hard all the way through. 1070 is one of those. The extra thickness hold too mus=ch heat and can either not harden evenly, or auto-temper to a lower than desired hardness. 1070 can require a brine quench on some thicket blades. Fast oils, like Parks #50 will work but you need a sufficient quantity to make sure the oil doesn't heat up.
 
You must log in or register to reply here.
Back
Top