Another Heat Treat Question...

CDHumiston

CDHumiston

KNIFE MAKER
I've been reading every heat treat thread I can find and I keep coming across a very similar process for 1084. This has to do with heat treating in a small gas forge.

I need to start by saying I'm doing strictly Stock Removal with steel from Admiral and Alpha. I am not Forging, just using the small forge to heat treat until my oven arrives.

The question is about the Normalizing process. Is it really necessary when doing stock removal with know steel? I get the idea that it's not, but I'm unsure...
 
CDHumiston said:
Is it really necessary when doing stock removal with know steel?
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I think the answer comes down to if you want to be sure the knife has the optimal grain structure of if you want to be pretty sure the knife has it.
How is the steel when you get it from the supplier? Is it cold/hot rolled? annealed? spheroidized?
 
billyO said:
I think the answer comes down to if you want to be sure the knife has the optimal grain structure of if you want to be pretty sure the knife has it.
How is the steel when you get it from the supplier? Is it cold/hot rolled? annealed? spheroidized?
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The steel is cold rolled and annealed. Some of it is also flat ground.
 
Alpha claims that their steel ships in optimal condition, ready to harden with no thermal treatments necessary prior to austenitizing. Probably accurate.

I've seen no such claims from admiral but they will provide CERTS and heat numbers which likely list the internal condition of the steel.
 
CDHumiston said:
The steel is cold rolled and annealed
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If in that order, then it should be fine. But if it's annealed then cold rolled, I'd normalize. Don't forget that cold rolling is a form of forging, so the steel will have added stresses in the microstructure that proper normalizing/annealing will take care of.
J. Doyle said:
no thermal treatments necessary prior to austenitizing. Probably accurate.
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This.
 
My steel for this batch of knives is from Alpha. I'm going to skip the normalizing and see how it goes.

I'll test the hardness when I'm done and may sacrifice a knife to look at the grain structure...
 
Chris, you don't have to sacrifice a knife, use a coupon to test the HT process and grain structure. A small piece 1"X2" or even 3" long would give you all the info needed without breaking a knife. You mentioned testing the hardness - do you have an Rc tester?
 
KenH said:
Chris, you don't have to sacrifice a knife, use a coupon to test the HT process and grain structure. A small piece 1"X2" or even 3" long would give you all the info needed without breaking a knife. You mentioned testing the hardness - do you have an Rc tester?
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Thanks, I do have an RC Tester. I just completed one knife this afternoon and it tested 62HRC.

I brought my forge up to 1490 and stabilized it pretty well. I do have a high temp sensor in the forge, but it does fluctuate a bit and some parts of the forge look hotter than others. I make sure to move the blade around inside the forge to try and keep uniform heat and color in the steel.

I did the heat treat in the garage so I could judge the color of the steel.

I quenched in 190 degree canola oil. Cleaned the oil off and put it in my regular oven at 400 for 1:30 minutes. Then I plate cooled it in aluminum plates for 10 minutes.

I'll try and work on some coupons tomorrow and try a few different things.
 
Sounds like you've got it covered. Be sure to post your results when you've completed your testing, or each phase of steps. We all enjoy watching folks test stuff :)
 
KenH said:
Sounds like you've got it covered. Be sure to post your results when you've completed your testing, or each phase of steps. We all enjoy watching folks test stuff :)
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I'll try and document things more. I need to start taking notes so I remember what works!
 
My second blade was larger and it came out of the heat treat at 57HRC. I put it back in at 425 for another hour and it's 61HRC now.

I really need to do some coupons so I can snap them and see the grain structure...
 
CDHumiston said:
My second blade was larger and it came out of the heat treat at 57HRC. I put it back in at 425 for another hour and it's 61HRC now.

I really need to do some coupons so I can snap them and see the grain structure...
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You gained 4 Rc points AFTER tempering hotter?

What steel type? And where on yhe blade are you testing your Rc?
 
J. Doyle said:
You gained 4 Rc points AFTER tempering hotter?

What steel type? And where on yhe blade are you testing your Rc?
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The steel is Alpha 1084 and I'm testing half way down the blade about 1/2" from the spine.

The blade may not have been properly cleaned up before the first test?

I did check my tester calibration with a certified steel puck and it was within .2HRC
 
CDHumiston said:
My second blade was larger and it came out of the heat treat at 57HRC. I put it back in at 425 for another hour and it's 61HRC now.

I really need to do some coupons so I can snap them and see the grain structure...
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If you're saying the 57 Rc was when it came out of first temper, then I'm betting the blade wasn't clean or something for the first Rc test, or perhaps one of those "bad tests" that happen sometimes. You can pretty well bet for simple steels that will test lower each time you increase the tempering temperature the Rc will decrease. Just as a note a couple different sources I've seen give more around 57 to 59 Rc when tempered at 425 Rc. The datasheet gives 392F for 61 Rc.

I just found this from NJSB for 1080 which will be VERY similar to 1084:
 
if you have steel from Alpha or Aldo(NJ Steel Baron) you shouldn't need to normalize it doing stock removal. just one more chance for an error. for your forge, get a piece of steel 1"x3" tube and place in the forge as a muffle. temps inside should be pretty even so you can control the temp easier. McMaster/Carr sells several different high temperature thermocouples and displays for reading your temps
scott
 
scott.livesey said:
if you have steel from Alpha or Aldo(NJ Steel Baron) you shouldn't need to normalize it doing stock removal. just one more chance for an error. for your forge, get a piece of steel 1"x3" tube and place in the forge as a muffle. temps inside should be pretty even so you can control the temp easier. McMaster/Carr sells several different high temperature thermocouples and displays for reading your temps
scott
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Actually, that's not correct with Aldo (NJ Steel Barron). There are numerous threads on multiple forums detailing several types of Aldo's steel and their heavily spheroidized condition, requiring (sometimes extensive) normalizing.
 
J. Doyle said:
Actually, that's not correct with Aldo (NJ Steel Barron). There are numerous threads on multiple forums detailing several types of Aldo's steel and their heavily spheroidized condition, requiring (sometimes extensive) normalizing.
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I've read this as well as I've been trying to determine if I need to normalize Alpha 1084. I didn't and it worked out fine...
 
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