Hello! I have a question on a problem I am having. First off let me tell you my process. I'm using 1080 steel from admiral. This was a forged blade, it has been thermo cycled at the following temps in a kiln, 1550, 1450, and 1350. After that is was rough ground and left rather thick say .060 at the cutting edge. I did this on purpose to hopefully be able to grind away any mistakes. It was heated to 1475 and held for 10 minutes and quenched in parks 50 at 70 degrees. I tempered twice for 2 hours at 415. Now the issues I'm having are a auto hamon which I do not want as this was going to be one of my JS knives, and the second issue I have is I have almost a Damascus pattern in spot all over the blade that I can not grind out! I'm super thin now (.010) at the cutting edge and can grind no further. In very bright light such as daylight you can not see it. You put it in low light and it shows up like a sore thumb. What am I doing wrong? This is the only piece of this steel that I have so I can't take pieces and test different methods with it. I'm pretty sure I'll have to toss this one which I'm not too happy about.
Auto-hamon: Agitate. Your tempts sound good so you need to increase your quenching rate and the quickest way would be to agitate more aggressively.
The patterning is alloy banding. There is no getting rid of it now, but normalization between the annealing and the final quench will zap it. Also, you may want to simply stick with 1450°F or 1425°F for your cycles, the 1350°F could accentuate the banding. Better to finish the cycles at 1275°F-1300°F for annealing heats to avoid this.
along with what Kevin said, I have had good experience with bumping the initial temp, up to 1650 the 1075/1080 can over refine in forging resulting in a lowering of the hardenability. I found bumping the initial normalizing temp can bring that back in line and give you a controlled starting point for your thermocycling.
MP
Thank you gentlemen for your expertise! Wish me luck!
I have had the EXACT same issue with this steel. I use it for some commercial I do. That alloy banding is a real nuisance.
The only way I've been able to eliminate it is just like Matt says - the initial soak is about 45 minutes at 1650. I follow that by 45 minutes at 1550 and an a final one at 1250.
I don't know why it works - but it does.
I also austenize in a controlled forge at 1495. I do use a hotter temp on my Parks of about 100 degrees.
That's my $.02.
(Additionally, I use some 1085 from a different source that requires a different schedule. Go figure.)
Well guys, thanks for all the info. It appears that this last batch of knives turned out A OK! I did as instructed I thermo cycled the steel at 1650 but only soaked for 20 minutes then 1550 for 20 minutes and finally 1250 for 20 minutes. I also heated my parks 50 to 80 degrees. I did have some decarb, but it was minimal. Once again thanks for the info!
