1080+ Tempering

Robert66

Robert66

Well-Known Member
It has been recommended from Dogs experts that I temper 1080+ at 2 1 hour cycles

2 questions I need to be sure of.
Does the 2 x 1 hour cycles apply irrespective of knife size, small and large, at the suggested above temperatures I get a nice straw colour before the 2 hours is up on a small knife.
When after the first 1 hour cycle must the second cycle start?

Sorry to labour this point but it bothers me.

Thank you
 
1080 doesn't form much retained austenite in heat treating. It just doesn't have enough carbon in it to cause a problem that way. Two one hour cycles would be fine. A single two hour cycle should work fine too but it's up to you. It also doesn't matter all that much how much cooling time you have between cycles as long as the blade cools. If your schedule doesn't allow you to do both cycles on the some day you can do the second cycle the next.
 
Personally, I temper everything for 2 hours, X 3 cycles. Testing has shown that at least two cycles are necessary for most steels, and #3 is simply an insurance policy. Just for the sake of continuity and workflow, I temper everything for 3, 2 hour cycles, allowing the blade(s) to cool to room temp (naturally) between cycles.

This thread made me think...... if you haven't done so, Kevin's (Cashen) video on heat treating 1084 is likely one of the best investments you can make if you have questions or hows and whys on heat treating carbon steels.
 
Yup, that's a great video, although I wish it was Narrated by some celebrity hottie. Staring at Kevin for a couple hours.....well, you know.
 
Totally agree on the video. Picked up a copy at the Blade Show, and have used it exclusively for heat treat process, particularly the spheroidal annealing process. The really gives you a soft blade that is easy to machine versus conventional lamellar annealing. I was really impressed at the difference after trying this process.
 
Doug Lester said:
1080 doesn't form much retained austenite in heat treating. It just doesn't have enough carbon in it to cause a problem that way. Two one hour cycles would be fine. A single two hour cycle should work fine too but it's up to you. It also doesn't matter all that much how much cooling time you have between cycles as long as the blade cools. If your schedule doesn't allow you to do both cycles on the some day you can do the second cycle the next.
Click to expand...

Thank you very much CB., I gratefully rely so much on the experience, knowledge of others.
 
Wow guys, thanks for the incredibly kind words on the DVD. To simply get the job done 2 hours at temperature is standard, but I find that with my process of walking in the Rockwell with multiple cycles or the time needed for the blade to reach temperature in an oven it can often be more than that total. My numbers have shown a homogenizing effect on the numbers, even in steels as simple as 1080, with multiple cycles. I would say that many of my blades see from 2.5 to four hours at temperature before I get what I am looking for, this is with heating other than the standard oven and I would expect everybody to have to dial in their own process to suit their way of doing things.
 
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