Heat treating O1 tool steel

[WBE]

Originally Posted by ranger1

A simple way to do a usable heat=treat is to put table salt on the blade. Correct me if I'm wrong but I believe it melts at about 1425 deg F. I have used this on some fun competitions where we had to make a serviceable knife in 2 hrs. With no other way to tell temp. it works pretty well. But, I normally use 1084 for these demo's

Hi Ranger. Acually common table salt melts at 1474? / 1475?. So your temp is dead on for many steels. The problem with the salt is having it on the blade where you need it, but it is certainly better than nothing. If nothing else, it may used to gauge and compare color better than guessing.

[WBE]

Non-magnetic is 1414?, consistant, the Curie point in iron/steel, so if using color as a gauge in simple steels to get to 1450? / 1500?, one or two shades of red hotter than non-magnetic will come in pretty close.

[WBE]

The more I think about Mr. Cro, the more I think his posts were all a part of some weird joke. Either on us, or on Cro himself. Much of what he said is just too ridiculous. Like he was "Asked by a member to come over and help us out"? Too weird to be real. This Cro thing is a joke gentlemen. We have been suckered in to spending our time replying to nonsense for some unknown persons warped sense of humor. Think about it!

[Doug Lester]

You may be right, WBE. He might have been a troll but he also wouldn't have been the first time that someone read a couple of articles and decided that he knew more about knife making than everyone else. That bit about burning the carbon out of steel I've heard of before as an old wives tale attributed to some old time blacksmiths. It will be interesting if he shows up on Ed Caffrey's discussion board.

Doug

[R. Yates]

the Name is Samuel Cro as in the Apache name sorry my mother did not watch the show as it was not around when i was born , here is what i was going By .

http://www.navaching.com/forge/heattreat.html

And yes I do make knives as well as fix a ton of farm equipment for folks around here .

and forging above the required temperatures for any steel does burn the carbon that is in the steel .

Sam

[Ray Rogers]

I hope everyone will pay close attention to what I am about to say and that is that I will absolutely insist that conversations, especially those directed to Mr Cro as well as those from Mr Cro , adhere to the rules of civility that have always been the hallmark of the Knife Network. Civility is what makes the Knife Network different from most other forums and it is probably the main reason many of us hang out here so believe me when I say we are not going to change directions just because we don't see eye to eye on any given subject. I do understand what is causing the friction but this isn't the first time we've had to resolve different views of any given subject and it isn't likely to be the last.

Make calm arguments for whatever your position may be and, if necessary, back it up with quotable science. If everyone keeps an open mind the truth will win out. Be as persuasive as you can without getting yourselves banned ....

[R. Yates]

Thank you Sir for a good site I do enjoy the site you and the Community have Built . as my personal life has been attacked, I will not post on this thread any more . However I will try to help others as I can on other threads .

Best Regards

Sam

[ranger1]

WBE, sorry I meant 1475F . I agree color is a great way to tell temp. but, it takes time to learn. I can judge color temp pretty good in my shop. But I am used to the ambient light in my shop. I just thought this would be a good simple way to tell quench temp for a beginning maker.

[WorkHorse]

Okay, well I am a beginner I have just read a lot of posts on heat treating steel and I have been reading what happens a molecular level. The reason I had thought about using O1 tool steel is because it was used to make a couple of knives that I own and I have read about using it. Though now that I have read more I have decided to go with 1084 steel due to the high carbon content and it is more forgiving.

[ranger1]

workHorse, You know you are only about 30 miles from me and you are welcome at my shop anytime. Just let me know when you'd like to come by. i live in Lexington straight down I-85. I don't know much but am glad to share what I do know.

[Doug Lester]

Yes, there are a lot of opinions out there and I started out with 1095 just because I read about it in a book by a known maker. Just like O1, it can be used but there are more forgiving steels to start with. Some of the problem is that the information can be old and the alloys can change a bit over time. Even the 1084 from Aldo and the 1080 from AKS are not the same steels that you read about in some of the older books. Sometimes you just have to experiment a little and go with what works for you.

I've had good results with 52100 but I'm dropping it and going back to one of the other simpler steels just simply because I will be more likely to have consistent results with something that is more forgiving of not having close temperature control.

Doug

[AUBE]

Originally Posted by Sam Cro

http://www.navaching.com/forge/heattreat.html

And yes I do make knives as well as fix a ton of farm equipment for folks around here .

and forging above the required temperatures for any steel does burn the carbon that is in the steel .

Sam

Unfortunately the link isn't opening for me so I can't comment on it specifically, I will try again later.

But as for carbon being burnt out.....as I mentioned in my previous post it is very time/temperature dependent. Initially we were talking about heat treating temps, now you mention "forging above the required temps...". Keep in mind the hardening temp (austenizing temp) and the forging temp are not the same thing.

The higher the temp, the faster the carbon diffuses. At 1500 (austenizing temp of O1) loss of carbon due to diffusion is minimal...you would need to leave the steel soaking in an oxygen rich environment for hours for it to affect the steel, and the soak time for a cross section the size of a knife in O1 is just minutes.

Now forging temps are much higher, around 1900 degrees. At those temps carbon moves much faster. If you were to "go above" the recommended forging temps, in an oxygen rich environment, then yes carbon diffusion would be much faster.

You are much more likely to lose carbon forging for a few minutes at the recommended forging temp then you are for heat treating at the austenizing temp. At slightly above the curie point, carbon diffusion simply is not an issue at the times we are talking.

Theres science to back this up. Google terms like "carbon diffusion rate in steel", "steel decarborization", "decarburization temperature of steel". You will find diagrams, formulas, charts, and even pictures of the steel taken by microscope of decarburization at different temps.

I think this paragraph sums it up nicely "Temperature and time are factors affecting the rate of decarburization. The higher that the temperature is the faster the decarburization will occur. A tool steel austenizing at 2000 degrees F will decarburize much faster than a tool steel austenizing at 1600 degrees F. Steel grades that harden below 1600 degrees F, generally don?t require protection from oxygen. Steel grades that harden near 2000 degrees F will decarburize within a few minutes, if exposed to oxygen." ( http://www.simplytoolsteel.com/heat-...oxidation.html )

Also keep in mind that if the environment is carbon rich and the conditions are right, you can actually gain carbon, not lose it....thats called "carbidizing"

[AUBE]

Originally Posted by Ray Rogers

.. adhere to the rules of civility that have always been the hallmark of the Knife Network. Civility is what makes the Knife Network different from most other forums and it is probably the main reason many of us hang out here...

Thats definitely what has me being active here. The bigger forums have a lot more traffic but in my opinion this forum has the best vibe.

[AUBE]

Originally Posted by Sam Cro

http://www.navaching.com/forge/heattreat.html
Sam

Ok the link finally opened for me. For those of you not familiar with this method of heat treating its called "marquenching" or "martempering". It can create a tougher blade at a given rockwell hardness. One main advantage is the really cuts down on warpage/cracking issues.

The downside is you have to get the reduction of temp just right or the steel won't properly harden. The method he used is an interrupted quench with brine..you can also buy salts/oils made specifically for doing this type of heat treatment and it will take the guesswork out of the process.

If you want to learn more about it you should find posts by Mr. Kevin Cashen...its a process he uses often in his blades.

[WBE]

Originally Posted by ranger1

WBE, sorry I meant 1475F . I agree color is a great way to tell temp. but, it takes time to learn. I can judge color temp pretty good in my shop. But I am used to the ambient light in my shop. I just thought this would be a good simple way to tell quench temp for a beginning maker.

I did not say that color is a great way to judge heat. It is really a very poor way, but for some it may be the only way. The salt could be a tool for someone to learn that particular color range by.