Thread: A. See Brand Voltage Temper??

Confusion: Is it hardened or tempered? There has been an historic misuse of tempering to describe the hardening process, as in heat and quench, and tempering, as in stress relieving or "drawing back the hardness." I think this was always called "hardened and tempered" and the understanding was that you could not have a tempered blade unless it was first hardened and so the assumption and common use was shorted to tempered steel and everyone understood what was meant. It's potentially imprecise. I don't care what you use as long as when a question comes up that I understand what you meant.

Induction heating is a common industrial process. It could be used with good effect if heating before quenching, aka hardening not tempering (preferred semantic precision). It has the potential to adjust for thermal control but is generally an open air process and there is a risk for scale formation. It is highly adaptable to odd shapes or small areas of precise heat.

For that matter I would not be surprised to see a razor company using an induction heat process before forging the blanks to shape. The European companies still use the molten lead baths for heat before quench as is their well established tradition. It gives precise temperature control and does not expose the steel to oxygen during heating.

Right, I also understood that tempering was a process that took place after quenching. Re-heating the blade to make it less brittle. Am I on the same page as you?
Sooo, voltage could be used to temper steel, but isn't necessarily the best method.

I realize I am regurgitating your words in a dumbed-down less technical matter because, well, it's not my area of expertise whatsoever.

Thanks for clarification

Originally Posted by brooksie967

...Re-heating the blade to make it less brittle. Am I on the same page as you? Sooo, voltage could be used to temper steel, but isn't necessarily the best method. ...

Yes, you could use induction heating to temper (draw back the hardness), but at the usual tempering temperatures, a good electric oven with an acceptable controller would be sufficient. At 400F there won't be enough interaction with oxygen to worry about. An induction unit would be prohibitively expensive when an oven would do the same job for a lot less money. Plus a normal tempering cycle will run from one to several hours and mounting a piece of steel to hold inside an induction coil would require some serious creativity.

A lot of makers who are strapped for cash will use a toaster oven. Personally I don't care for the amount of variability in the set point. Some can swing as much as 50 degrees high or low. That's okay if you're willing to live with the risk. I like to have a little more precision.

I know some folks (myself included) who have used the good old kitchen oven. It might be a little more precise than the toaster oven. You may take your life in your hands if you quench in some stinky version of used motor oil or transmission fluid. If the cook/baker catches you doing that you may well die in your sleep.

It is for this reason, I have used canola oil for many many years. And live to tell you this tale....