decarb layer?

[MarkJeffrey]

I find any time I've used 1084 I've been some what skeptical that my heat treat went as well as the usually 01 and 1095 I've been using. I can only rely on the file test at the moment, but it sure doesn't skate off of this like other steels I've worked with. The second time I did the quench I just kept filing the edge (more just because I was slightly upset :grumpy: ) but I did indeed hit hard steel. Any other steels I've never had that happen.

HT process was - using an evenheat
1600 cool to black, 1500 cool to black, 1450 cool to black, 1300 cool to black, all quenched in water once black. This knife was stock removal but I figured I go the extra mile to get the most out of the blade in the end (?)
1500 soaked for 10 minutes and quenched in 130* canola oil.
It is now in the oven tempering at 400


So with all that, I guess my question is how DEEP can a decarb layer be? Or am I even asking the right question here?

 

[javand]

It can be pretty deep depending on times and temps.

One thing you could consider doing, and what I do with many of my damascus billets for customers, is to do your thermal cycling before you rough grind. Then, do your grinding, hardening, etc. Personally I recommend doing a 1200 degree stress relief cycle (which shouldn't contribute any decarb) before hardening.

The short soak from hardening should give very little decarb, such that it'll easily clean up with the usual belt progression afterward.

FWIW, most recommend doing two normalizing cycles (1600 deg), and it's good you're doing this full thermal cycling with 1084. It's necessary to get the best performance IMO.

 

[MarkJeffrey]

Thanks Javand