harden and temper 8670?

[Willie71]

This is worth reading.

https://www.bladeforums.com/threads/8670-heat-treat-coupon-results.1559745/

 

[Willie71]

Its not a forge in any real sense. I have no equipment suitable.
I have several large clay building blocks that I put together loosely, leaving only enough space for the blade. But I only have one MAPP blowtorch.
I have a handheld digital thermometer that will reach a 1000c with a metal probe. I got the temp up to 600c, but without a second mapp torch i just cant get the last step of the way.
I have no extra cash to spend on this experiment, if I cant get the whole blade to 830c then my only other options are to either edge quench, or just leave it as a soft wall hanger / conversation piece.

Mail it to me and I will heat treat it for you.

send me a message at wjkrywko at gmail dot com.

 

[Stacy E. Apelt - Bladesmith]

He lives in Cyprus. Mailing the blade would cost a lot.
Best option would be to have a maker on Cyprus do it for him. Natlek might know of one.

 

[Alpha Knife Supply]

That chart from alpha knife supply is wrong for our application and they have said it’s not correct for our use so no idea why they leave it up to confuse people

"they have said it’s not correct". I have never said anything like that.

When we received our first batch of 8670, we were concerned about the low tempering temperatures. We verified with the mill that the temperatures sent were correct. We made some knives and used the austenitizing and tempering temperatures the mill recommended. The video below shows a test chef knife made from .100" ground to a zero edge being hammered through steel tubing. Finished hardness is 63 RC.

We suggest heat treating temperatures recommended by the mill who made the steel. Some alloys have additional heat treat recipes that are significantly different than the mill recommendations. Z-Wear is a good example. The mill recommends tempering around 1,000°F, and we tell knifemakers that is what the mill recommends. However, some knifemakers like Warren have extensively tested lower tempering temperatures and have had excellent results. I'm glad some knifemakers push the limits of steel.

Chuck

 

[Joshua Fisher]

"they have said it’s not correct". I have never said anything like that.

When we received our first batch of 8670, we were concerned about the low tempering temperatures. We verified with the mill that the temperatures sent were correct. We made some knives and used the austenitizing and tempering temperatures the mill recommended. The video below shows a test chef knife made from .100" ground to a zero edge being hammered through steel tubing. Finished hardness is 63 RC.

We suggest heat treating temperatures recommended by the mill who made the steel. Some alloys have additional heat treat recipes that are significantly different than the mill recommendations. Z-Wear is a good example. The mill recommends tempering around 1,000°F, and we tell knifemakers that is what the mill recommends. However, some knifemakers like Warren have extensively tested lower tempering temperatures and have had excellent results. I'm glad some knifemakers push the limits of steel.

Chuck

The chart shown on our website is based on the information from the steel company. It is a chart for sheet, not thicker material.

We've also gotten better results than shown on the chart. I think the numbers released by the steel company are for "the lowest common denominator". In other words, people who are participating in this thread will get better results because they are interested in doing the best heat treatment possible. Someone who heats the blade non-magnetic and quenches in used motor oil will probably not get close to the published numbers.

Chuck

Chuck please reread what I said and don’t cut my post out of context, I didn’t say those numbers where wrong but they are wrong for our use which is exactly what I said and what you implied in the past. In my opinion by posting a chart that is correct for different industry is misleading for your buyers, it would be better to say based off our tests we recommend this temperature to quench and these temps for tempering instead of just slapping up a chart from the mill that may not be what is best for knife makers.

 

[Willie71]

"they have said it’s not correct". I have never said anything like that.

When we received our first batch of 8670, we were concerned about the low tempering temperatures. We verified with the mill that the temperatures sent were correct. We made some knives and used the austenitizing and tempering temperatures the mill recommended. The video below shows a test chef knife made from .100" ground to a zero edge being hammered through steel tubing. Finished hardness is 63 RC.

We suggest heat treating temperatures recommended by the mill who made the steel. Some alloys have additional heat treat recipes that are significantly different than the mill recommendations. Z-Wear is a good example. The mill recommends tempering around 1,000°F, and we tell knifemakers that is what the mill recommends. However, some knifemakers like Warren have extensively tested lower tempering temperatures and have had excellent results. I'm glad some knifemakers push the limits of steel.

Chuck

I think Josh is referring to the issue that 1525f, and 350f temper leave you above Rc60, almost Rc61, and the chart would be a few Rc points lower. If a second chart with the numbers Larrin and I got from the samples was also posted, it would be helpful.

 

[Joshua Fisher]

I think Josh is referring to the issue that 1525f, and 350f temper leave you above Rc60, almost Rc61, and the chart would be a few Rc points lower. If a second chart with the numbers Larrin and I got from the samples was also posted, it would be helpful.

Thank you Warren that is what I was referring to and what I meant by wrong for our use. I’d love to see more information, I’ve had great results with this type of steel and enjoy seeing the science behind it. If I came across as harsh I didn’t mean it that way.

 

[Natlek]

The ideal temp for when the blade hits the oil is 1525 so bring it up to around 1550 cause it will lose some heat in between your oven and quench tank you don’t need a full 5 minute hold or soak with 8670 2-3 minutes is fine.

I highly recommended to you to buy and read several times book from Dr. Larrin Thomas . Just friendly advice

 

[Joshua Fisher]

I highly recommended to you to buy and read several times book from Dr. Larrin Thomas . Just friendly advice

Thank you, I already realized this wasn’t needed as Larrin pointed out, it was old information that I had heard to go past your target temp. It’s aways good to be open to new information and I think anyone could benefit from Larrins book.