1084 ht

Erdbeereis

Well-Known Member
I know this has been asked hundreds of times, but is this a good procedure for HTing a stock removal knife from Aldo's 1084?

1. Profile, and bevel.

2. Normalize 3 times. (IS THIS NECESSARY ON A STOCK REMOVAL KNIFE? HOW WOULD I GO ABOUT NORMALIZING?)

3. Raise the temp to non-magnetic and let soak about a minute longer.

4. Quench and let cool in 120-130º canola oil agitating up and down. (DO I HAVE TO REMOVE THE HARDENING SCALE BEFORE TEMPERING?)

5. Temper twice for two hours each at 400º (IS THIS GOING TO GET ME AN RC OF AROUND 60?)

Thanks for the help! :)
 
Whether or not you harden and temper before or after you grind your bevels is up to how it works for you. You could try it both ways to see which works for you best.

Normalization is still good even when starting out with annealed steel, especially if you profile and grind in the bevels before hardening and tempering, just to make sure if for no other reason. There can be some stresses put on the steel during grinding and normalization will help relieve that. It will also make sure of the grain size, if done correctly. However to normalize, you will have to get the steel above critical temperature. Some people do it with three heats that are descending in temperature, like 1550°, then 1450°, and finally 1400°.

To harden, heat the steel to an non-magnetic state then get it just a little brighter. Try to hold it there for 2-3 minutes. Don't let it get much brighter or you could grow the grain.

The canola oil quench looks about right. Allow the steel to cool to room temperature before tempering to make sure that the conversion of austinite to martensite is complete. The double temper at 400° should work. Steels like 1080 form little retained austinite so two cycles should be fine. You could do a third cycle if you want for insurance but I doubt that it's necessary. I scrub the oil off with wire brush with detergent after cooling and before tempering which gets rid of most fire scale. If you have some present after tempering you could soak the blade in white vinegar over night.

If the blade seems to be too hard after tempering at 400° you could do one more cycle 25° hotter.

Doug
 
Thanks for the help!

So for normalizing, I would heat it up a bit over non-magnetic and let air-cool? Then do it twice more?
 
have had zero issues heat treating 1084 without normalize. heat steel to 1500. soak at 1500 for about 10 minutes, try and keep the temperature +/- 25. quench. I use an old towel to remove the oil and it takes off most of the scale. I have also used a green or red scotchbrite pad to remove scale. temper at 350 for 2 hours. using Parks50 quench, this procedure gives me Rc62-63. if any oil remains on the blade prior to temper, your wife may yell about the smell.
scott
 
There can be some stresses put on the steel during grinding and normalization will help relieve that. It will also make sure of the grain size, if done correctly. Doug

I think normalizing is a good idea, even on stock reduction blades with this alloy, for the same basic reasons Doug mentioned.
 
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