Heat treat question

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ddm4elite3442

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Mar 16, 2017
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I’ve been using 3/16” and 1/4” stock of 1084 and 80crv2 for my knives. After heat treat I end up with a HRC of 61-62, so my question is this... if that’s the hardness I want for my blade, should I temper it anyways at the 375-400 degrees twice for 2 hrs ? And if I do temper at that heat, will I still end up with a HRC of 61-62 or because it’s at 61-62 from HT, will the temper temp bring the HRC down ?
 
The question you should probably be asking yourself is why are you getting 61-62 out of the quench. If you check out Kevin Cashen’s site and click on his heat treating link, you will find some very helpful information.
 
Here are the questions to answer for us to help you:
1) How is the HT being done and how are temperatures being determined?
2) What quenchant are you using and in what quantity?
3) How are you determining the RC 62-61 as-quenched number.

Two temper cycles is needed regardless of the hardness desired. Tempering converts the brittle martensite into tempered martensite.
 
Stacy E. Apelt - Bladesmith said:
Here are the questions to answer for us to help you:
1) How is the HT being done and how are temperatures being determined?
2) What quenchant are you using and in what quantity?
3) How are you determining the RC 62-61 as-quenched number.

Two temper cycles is needed regardless of the hardness desired. Tempering converts the brittle martensite into tempered martensite.
Click to expand...
Here’s what I have to work with an’ how I’m doin it...
1- I HT with a gas forge an’ thermalcouple. I follow the HT an’ temper process provided by NJ steel baron ( cause that’s where I buy my steel from ). I get the forge all nice n toasty then throw my blade in, get it to 1,480-5,000 an’ soak for about 5 min, movin’ the blade in the heat continuously.
2- I use canola oil heated to 130 degrees an’ when I quench the blade, I leave it in the quench for 10-15 sec. while movin’ back an’ forth ( in a spine to edge direction ).
3- all I have for HRC testin’ is the hardness files. 60 skates rite off the steel while the 65 gives a slight grab on the steel when runnin it across. So the 61-62 HRC is only a guess-timate. I could be gettin’ a 63-64 but I don’t have the money for a HRC machine or tool. So for now, I have to work with what I got.
My primary question was about tempering if I already had the HRC I wanted outta HT. An’ now I know, the answer is yes, I should temper after HT. I’ll appreciate any further advice anyone has to offer an’ thanks for all y’all’s help.
 
Last edited:
I would normalize at around 1600° Air cool to black.
Then do at least 2-3 more descending thermal cycles at 1550° Air cool to black, 1500° Air cool to black, and 1450°-1500° and on the last one quench, don’t worry about a soak, with agitation slicing front to back in the oil (don’t go side to side for fear of warping).
Check your hardness after you grind off the decarb layer.
Then temper to your desired hardness.
http://www.cashenblades.com/steel/1084.html
 
You want at least one gallon, and preferably two gallons for steel as thick as yours. Also, those are fairly shallow hardening and could use a faster quenchant like Parks #50.
Testing files are only a tad better than licking the steel to taste-test the hardness. They give a range that is very undependable and requires experience to read. They also are pretty useless on steel right out of the quench because of decarb. Grind the edge back a bit before testing and I bet the Rc65 file skids more.

As I say often - Ignore the RC numbers unless you have a proper tester. Most methods are just a guess anyway.
Follow the proper HT regime as stated by Josh in the previous post and use a suitable type and quantity of quenchant and you will hit the normal as-quenched hardness. Temper by the charts and you will be good.
 
Stacy E. Apelt - Bladesmith said:
You want at least one gallon, and preferably two gallons for steel as thick as yours. Also, those are fairly shallow hardening and could use a faster quenchant like Parks #50.
Testing files are only a tad better than licking the steel to taste-test the hardness. They give a range that is very undependable and requires experience to read. They also are pretty useless on steel right out of the quench because of decarb. Grind the edge back a bit before testing and I bet the Rc65 file skids more.

As I say often - Ignore the RC numbers unless you have a proper tester. Most methods are just a guess anyway.
Follow the proper HT regime as stated by Josh in the previous post and use a suitable type and quantity of quenchant and you will hit the normal as-quenched hardness. Temper by the charts and you will be good.
Click to expand...
Awesome !!!
Thanks Josh an’ Stacy, for the rundown on the process an’ advice : )
 
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