Heat Treat Question

J

J.D.

Joined
Feb 12, 2006
Messages
342
I have been looking around here for a few months now. I have a question that I hope someone can answer. After hardening a blade how important is it to temper immediately after hardening? I have a new Evenheat oven ordered and want to harden and temper in it, but I know it will take quite along time for it to cool down to tempering temp. I use 1095 and O-1 at this time, will do some 440-c later. Any help would be appreciated. J.D.
 
It's always a good idea to temper immediately but some will use a toaster oven or kitchen oven rather than using the HT furnace.Your wife won't object as long as you clean off any quenching oil.400 F will do for most things and you can always do 1 hour in the kitchen oven immediately then more tempering the next day.That's the safer way.
 
I use 1095 and put it in the freezer overnight between quench and temper. This helps convert austenite to martensite. Sometimes i don't get to tempering for a couple of days and have had no problems.

ron
 
It is best to temper immediately after quench.Technically,you should not let the blade drop below 200 degrees.In general,temper as soon as it is practical.
Chilling the blade (or doing cryo) should be after a snap temper is done (immediate temper at 200-300 after quench).Temper again after the cold treatment.
 
Actually, all of the tool steel manufacturer's specs that I am familiar with suggest cryo as soon as the steel cools to room temperature prior to tempering. Many people say to snap temper to prevent the risk of cracking. I have done it this way for several years without cracking any.

I do not cryo plain Carbon steels, just high alloy tool steels and a little stainless.
 
tempering in the kitchen oven is fine. Get yourself a thermometer to verify your temps.

Snap tempers aren't necessary for knife blades. I'd go right into cryo, or, your home freezer.

If you can't temper immediately, either go into the freezer, or temper 1 hour @300F.
 
I've never had a blade of simple carbon steel crack after quenching when I didn't get around to tempering until hours or days later.

It is best to temper asap though just to be on the safe side.
 
I thought the home freezer was were you kept your icecream from getting runny. I did not realize you could affect the martinsite content of your blades by putting them in next to the fishsticks.:confused: Fred
 
Fred.Rowe said:
I thought the home freezer was were you kept your icecream from getting runny. I did not realize you could affect the martinsite content of your blades by putting them in next to the fishsticks.:confused: Fred
Click to expand...
same here but i guess it cant hurt less it cracks
 
butcher_block said:
same here but i guess it cant hurt less it cracks
Click to expand...
As long as you don't have to move the cold beer to make room for the hot blades, I see no harm in the practice. :yawn:
 
Thanks for all the input to my queston, it helped alot. I got the new Evenheat oven the other day, it is great. The first blade to come out of it was such a pretty sight, a nice even color from point to tang.
Thanks again J.D.
 
Steve Hayden said:
Actually, all of the tool steel manufacturer's specs that I am familiar with suggest cryo as soon as the steel cools to room temperature prior to tempering. Many people say to snap temper to prevent the risk of cracking. I have done it this way for several years without cracking any.

I do not cryo plain Carbon steels, just high alloy tool steels and a little stainless.
Click to expand...

I started freezing blades after I saw in "Metallurgy Theory and Practice" a chart that showed plain carbon with 1% carbon could have as much as 15 to 20 % retained austenite at room temp. I figured if the freeze could convert more I would be a good thing.

ron
 
I think that the plain FeC steels will not have that much retained Austenite if given a sufficient soak at hardening temperature and then tempered twice for two hours each. The soak should anneal dislocations to allow the Martensitic transition to sweep through efficiently and the tempers should deal with any small amounts of retained Austenite.

In high alloy steels diffusion complicates the Martensitic transition and the alloying transition metals will act as dislocations or cause them by charge imbalances in the lattice.

In plain FeC the transition is a pure shear, diffusionless process that sweeps through the lattice at around 1 Km/second. Theoretically the retained Austenite should just occur in strain shadows created by the dislocations.
 
sunfishman said:
I've never had a blade of simple carbon steel crack after quenching when I didn't get around to tempering until hours or days later.

It is best to temper asap though just to be on the safe side.
Click to expand...
It is best to temper asap though just to be on the safe side
Click to expand...
yes for the two bigist reasons
in case you drop it on the floor or you forget you have to temper it..that would be me :)

simple carbon steels setting for days wouldn't bother me before Tempering.
if you do a good job in the H/T for these steels you don't need a cryo

the freezer is a good place to put the blade if you tend to forget where you put things :) it does you more good for that reason then the little bit of cold your are getting in there..you'll see little happening for you in a house freezer:)
this info is perticuly used on the simple carbon steels.
but like siad it can't hurt it any:)

SS is another matter for a full cryo..
just my 2 cents:)
 
I use 1095 all the time. And use the Evenheat oven as well and it will work great for hardening the 1095 at 1500 and It is best to temper immediately after quenching in oil and that needs to be about 125-140. When you temper the blades you can do that also useing the Evenheat by setting a new program for that. And it need to be about 350 for 2 hours, you can lay the blade out on something and let it set. Checking the harden using a Rockwell Tester. Please check out my shop and see my setup for that. God bless and you may call me on the phone for more help.

Barkes :thumbup:
http://my.hsonline.net/wizard/knifeshop.htm
1.812.526.6390
 
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