- Joined
- Aug 5, 2014
- Messages
- 213
Some days ago I forged out an integral bowie from 1 inch 1095 round stock. I spent a lot of time forging the whole blade, probably around 4 hours trying to get everything perfect. Following the forging, I let the blade cool and then took it to the electric oven.
I then normalized the blade in the electric oven in successive steps, then went to do an anneal sequence on it that I've seen Kevin Cashen recommend a lot. I've done it on a handful of other blades with good results. The sequence is hold at 1375 for 45 minutes and then cool to below 900 over a 10 hour period (no more than 50 degrees per hour).
The clincher is, I messed up and started the cycle but didn't see that it was set on "hold". Went to bed, came back to it next morning and saw the oven was still on at 1375. I then manually changed to the next step and ran the 10 hour cool down cycle. The blade must have been sitting at 1375 for 12 hours, and then on top of that it had the cool down cycle, so quite a bit of time, especially when adding in forging time.
After taking it out, wow, lots of scale. I actually measured the scale and it was .8mm thick on each side. Now in heat treat, this thing won't harden properly. I've done 3 attempts at hardening in Houghton's G Edit: I used Houghton's K Fast Quench oil and file cuts in enough to where I'd say it's a dud.
What I'm wondering is, at which point did I cause such a high degree of decarb that the steel won't harden? Did holding the steel for a 12 hours at 1375F (plus ramp down) kill it? Or is it more likely that I killed it in the forge? Just FYI I've used this exact steel a bunch already successfully and the forge is temp controlled so it's not likely it would have been way far above temp. I recall something where Kevin Cashen did a test where he held a steel at austenitizing temp for 5 hours without any detrimental effects to grain size, but perhaps decarb can still be an issue?
Thanks for helping me figure this one out, bummed because it was one of my favorite blades as of recent, but always good to learn something.
I then normalized the blade in the electric oven in successive steps, then went to do an anneal sequence on it that I've seen Kevin Cashen recommend a lot. I've done it on a handful of other blades with good results. The sequence is hold at 1375 for 45 minutes and then cool to below 900 over a 10 hour period (no more than 50 degrees per hour).
The clincher is, I messed up and started the cycle but didn't see that it was set on "hold". Went to bed, came back to it next morning and saw the oven was still on at 1375. I then manually changed to the next step and ran the 10 hour cool down cycle. The blade must have been sitting at 1375 for 12 hours, and then on top of that it had the cool down cycle, so quite a bit of time, especially when adding in forging time.
After taking it out, wow, lots of scale. I actually measured the scale and it was .8mm thick on each side. Now in heat treat, this thing won't harden properly. I've done 3 attempts at hardening in Houghton's G Edit: I used Houghton's K Fast Quench oil and file cuts in enough to where I'd say it's a dud.
What I'm wondering is, at which point did I cause such a high degree of decarb that the steel won't harden? Did holding the steel for a 12 hours at 1375F (plus ramp down) kill it? Or is it more likely that I killed it in the forge? Just FYI I've used this exact steel a bunch already successfully and the forge is temp controlled so it's not likely it would have been way far above temp. I recall something where Kevin Cashen did a test where he held a steel at austenitizing temp for 5 hours without any detrimental effects to grain size, but perhaps decarb can still be an issue?
Thanks for helping me figure this one out, bummed because it was one of my favorite blades as of recent, but always good to learn something.
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I'm in Thailand as a result of chasing a Swiss girl across the world, and I ended up out here for over 3 years at this point [emoji23][emoji5] The steel that we use is all under the JIS standard and is also available in a different range of sizes and thicknesses that I tend to see in the US. All of our 52100 here, for example, (called SUJ2) is only sold in rounds. 01 as far as I've found is sold in rounds as well as very thick bar (20mm minimum) and needs to be bandsawed to thinner sizes...I've done this for multiple orders I've placed. This steel is also only available in rounds as far as I know but it's the most popular steel for getting Hamon activity in the custom knifemaker scene here. People here call it the 1095 equivalent and make some beautiful knives from it. 