JTknives
Blade Heat Treating www.jarodtodd.com
- Joined
- Jun 11, 2006
- Messages
- 8,630
So I got another batch of 1084 blades that acted up during heat treat. The weird thing is I could tell right away during the first quench that something was up. After you have done as many blades as I have you have a feel for how a quench feels. By this I mean the tongs have a vibration to them as the oil quenches the steel. Hard to explain but with every steel that has failed to harden in parks 50 it has felt different. You can’t feel the turbulence as strongly and the blades come out with a black skin that does not wipe off. I attribute this to the steel not converting to martensite and the scale not popping off which disrupts the vapor jacket. But that’s just a theory.
Anyways here is the blades in question. I these blades these are full of soft spots. I have come across this before in the past and you could see them after surface grinding. We did a long clean up grind so we could have room for testing a few times during tempering. Well after we tested the first one at around 37rc we tested on both ends of the grind area. Some had a large swing in hardness and Others did not not. On blade measured 63 on one end and 53.5 on the other end, probably about 1/4” apart. I have included a few close ups of the test marks and you can see the drastically different depths of dimples. I have asked the customer to look for his order number so I can verify where it’s said to have come from. So just to be clear I’m not pointing fingers at anyone. I’m just posting these pictures to maybe start a conversation about this issue and how we can solve it. Yes these where normalized and quenched at the industry’s recommended standard temps.
Anyways here is the blades in question. I these blades these are full of soft spots. I have come across this before in the past and you could see them after surface grinding. We did a long clean up grind so we could have room for testing a few times during tempering. Well after we tested the first one at around 37rc we tested on both ends of the grind area. Some had a large swing in hardness and Others did not not. On blade measured 63 on one end and 53.5 on the other end, probably about 1/4” apart. I have included a few close ups of the test marks and you can see the drastically different depths of dimples. I have asked the customer to look for his order number so I can verify where it’s said to have come from. So just to be clear I’m not pointing fingers at anyone. I’m just posting these pictures to maybe start a conversation about this issue and how we can solve it. Yes these where normalized and quenched at the industry’s recommended standard temps.