quenching solution?

Fred.Rowe

Fred.Rowe

Joined
May 2, 2004
Messages
6,848
:confused: I have never been satisfied with the different types of oils I've used to harden my blades. Not that they don't do the job, it's the condition of the blade surface that makes fore so much work after hardening. Are there any products out there that quench cleanly with less cleanup afterward? I work with 10 series, L6, 52100 etc.
Thanks in advance, Fred
 
Fred,

Sure sounds as if your complaint is of decarburation and scaling, caused by oxydation (oxydization). If that be the case a change of quenchant will not cure or help but rather isolation from atmosphere while at and near critical temperature will. You know that :) .

RL
 
I've heard of some makers coating thier blades in some liquid Borax solution, letting it dry, and then doing the heat treat, and quench, where the stuff cracks off the blade in quench, leaving the blade with the finish it had prior to HT.

Another way is to coat the blade with a commercial coating for that purpose(turco?). Those that have used it report favorably. I believe that TKS, and maybe some others sell the stuff.

Good luck!:eek:
 
Fred,

Some few months back Bruce Bump bragged up Brownell's PBC to me and I bought some. It works up to 1650 degrees F, so the label claims, and I like using it very much. It cleans off the quenched blade in a couple to a few minutes in boiling water (a practically perfect temperature for holding a high carbon steel prior to temper). It is specified that the steel be heated to about 500 F and then coat with the powder. I have found my best results in consistant coating to occur if I hold the steel moderately above 500 F for several minutes to allow to equalize, then coating. I recommend Brownell's PBC Non-Scaling Compound. (VERY IMPORTANT: DO NOT allow it to stand in your heat treating oven. Use stainless wrap or an alternative material to catch any droppings or residue so that it can be removed from the oven after using. My reason: higher temperaturers, those for heat treating stainless steels - as an example, will cause the residue to eat steels and I don't know what else. Keep it off your refactory bricks and your electric elements and your thermocouples.)

RL
 
One way to solve this is to heat treat after forging, before grinding. This solves several potential problems, stops warping and saves several steps, grind once not twice, no scale if you use vinegar to remove it. Also a hard blade grinds more accurate than a soft blade just slower and you have to be careful to not get it too hot. Gib
 
When I first started I would heat treat the blade just after grinding in the profile and then grind all bevels after heat treat. Just like Gib said though, becareful not to over heat the steel and ruin you HT. I think most guys here do their final grind (after heat treat) bare handed so they can feel how warm the blade is and not over heat the steel.

I used to soak my leather glves in water and keep them wet when grinding with the course grits. That still gives you some protection from the grinding belt and the wet gloves really transfer the heat from the blade quickly so you don't over heat the steel.

Now I grind my knifes to about 98% of finished dimensions before heat treat and temper. Usually to a 320 grit and leave the edge at about 15 thou. I do a triple normalization starting at 1650 °F and work down to 1550 °F. I don't have a problem with warping.

I use 1095 carbon steel and 15N20. I use a preheated 50/50 mix of ATF and 10W40 for quenching. I austenize in molten salt at 1550 °F and quench in the oil at about 120 to 130 °F.

Blade cleans right off in hot water before temper. I get around 62 HRC as quenched and draw that down to 58 or 59 HRC during the temper. After tempering, I start hand sanding at 320 and take it to 600 before etch.

If you have the ability I would suggest bulding a molten salt set up. My set up is pretty simple, but effective. If you have any set up questions feel free to ask.
 
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