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Author Topic: stock removal heat treat.  (Read 3743 times)
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chad2
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« on: June 13, 2013, 05:16:21 PM »

So I must say first that I use 5160 steel almost exclusively. When I first started I was a big addvicate of fast and to the point heat treating. 

But after talking to ed caffery and ed fowler I came to the conclusion that I could get a lot more performance from normalizing , thermal cycling, and annealing three times each putting them into the freezer any time I could. And from my testing I have had a great improvement.

I have chosen stock removal because of living situation and money.

I have been talking to ed fowler lately and I am starting to think that the long proccess I have been using is not doing as much as I thought to a stock removal blade.

Hey ed I decided to post this instead of email because I thought that this topic could be good info for a lot of people.

Hey ed in your last email to me you said that, you will not have very much grain growth or any at all unless you go above 1725  this kind of makes me feel like there is not much I can do for grain refinment either unless I forge.

The way you worded the email you made it sound that my process really does nothing for making finer grain. Is this true?

If so is there anything us stock removal guys can do to increase  performance and refine grain.

My heat treat is.

Normalize = 3: 3 day, into house freezer overnight after each. 1550 degrees air cool.
Thermal cycle = 3: 1 day, into freezer over night after all three. 1380- 900 = one cycle
Anneal = 3: 3 days, each one cools in furnace over night. Into freezer after all three. 1550, 30 mins, 100 degrees per hour cooling rate.
Quench = 3: 3 days, 1545 degrees for 5 mins, oil is heated to about 160 degrees, into freezer after each quench overnight.
Temper = 3: 3 days, 400 degrees for 2 hours, into freezer after each cycle.

Have recently changed my annealing temp to ed fowlers annealing only i am going to use 1000 degrees.

These questions are for everyone who have maybe expieremented with this. Thanks ed and everyone else    

« Last Edit: June 13, 2013, 05:23:53 PM by chad2 » Logged
Daniel Rohde (D-Vision)
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« Reply #1 on: June 14, 2013, 07:21:20 PM »

Great question! I have the same set up as you and would love to hear thoughts to!!
Common guys!!  ( Huh)
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chad2
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« Reply #2 on: June 14, 2013, 08:48:50 PM »

Great question! I have the same set up as you and would love to hear thoughts to!!
Common guys!!  ( Huh)

Do you use 5160 or 52100 and do you do your own heat treating?
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mreich
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« Reply #3 on: June 15, 2013, 10:06:13 AM »

Chad, IMHO, a lot of your heats are quite a bit higher than I would use, even forging 52100 down from large stock.

I'm Not sure, but I think critical temps for 5160 are lower than 52100. You don't have an abundance of carbon with 5160 like you do with 52100.

Have you checked to see what temperature is "non-magnetic" in your kiln?

In mine, it's only 1460*F for 52100.

When you are completely relying on thermal cycles to refine the grain, you're temperatures are absolutely critical.

Have you broken or cut a piece of steel you've HTed, and compared the grain to others you've done, or the original steel?

You can get a pretty good look with a $15, 100x micro-micro-scope from amazon. Radio Shack carries one Very similar, but it's bigger, so the light doesn't work nearly as well. You will find that getting the right light is crucial to seeing anything. 
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Daniel Rohde (D-Vision)
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« Reply #4 on: June 15, 2013, 03:26:35 PM »

I did use 5160 because I couldn't find 52100 in flat stock but I fond a nice place to get it so now I use 52100 and some 1095 I hope to do some forging soon but I working on the set up
this is the site I use for 52100 I haven't done much testing yet but seems to work good (it takes a wile to make blades so I normally only test blades I don't like) http://newjerseysteelbaron.com/shop/
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wnelson aka. dedox
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« Reply #5 on: June 15, 2013, 04:35:34 PM »

Yeah, i really like that steel Smiley.
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chad2
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« Reply #6 on: June 15, 2013, 09:16:07 PM »

Chad, IMHO, a lot of your heats are quite a bit higher than I would use, even forging 52100 down from large stock.

I'm Not sure, but I think critical temps for 5160 are lower than 52100. You don't have an abundance of carbon with 5160 like you do with 52100.

Have you checked to see what temperature is "non-magnetic" in your kiln?

In mine, it's only 1460*F for 52100.

When you are completely relying on thermal cycles to refine the grain, you're temperatures are absolutely critical.

Have you broken or cut a piece of steel you've HTed, and compared the grain to others you've done, or the original steel?

You can get a pretty good look with a $15, 100x micro-micro-scope from amazon. Radio Shack carries one Very similar, but it's bigger, so the light doesn't work nearly as well. You will find that getting the right light is crucial to seeing anything. 

I have a paragon kiln and I keep a close eye on the temp also
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« Reply #7 on: June 16, 2013, 09:59:19 AM »

I understand, but what you are looking for is what temperature in your oven the steel you are using becomes non-magnetic.

You have a nice kiln, and that's great! However, it takes more than a nice oven with digital readout to determine critical temp. They don't call it "critical" because they mean "approximately".

I have read all kinds of different temperatures to use for different heat cycles. The fact that they aren't the same tells me something.

Not all 52100 works the same. I had to determine things for myself. 50* one way or the other can make a significant difference. The exact alloy of your steel makes a difference.
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chad2
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« Reply #8 on: June 16, 2013, 11:42:01 AM »

I understand, but what you are looking for is what temperature in your oven the steel you are using becomes non-magnetic.

You have a nice kiln, and that's great! However, it takes more than a nice oven with digital readout to determine critical temp. They don't call it "critical" because they mean "approximately".

I have read all kinds of different temperatures to use for different heat cycles. The fact that they aren't the same tells me something.

Not all 52100 works the same. I had to determine things for myself. 50* one way or the other can make a significant difference. The exact alloy of your steel makes a difference.


That is some good advice. I am going to have to test this. But critical temp from what I have read is actually higher then the non magnetic state of simple carbon steels. Yes 5160 steel goes nonmagnetic at around 1460 but you actually need to get it up to around 1500-1550  for the steel to fully harden

Also another thing we need to pay attention to is how much the steel is cooling from the time you open the kiln door to the time you get it submerged in the oil. Critical temp is the temp it needs to be at when it hits the oil so going above that temp to make up for the degrees lost will be ok as long as you are not doing extended soak times.

If I am wrong about this please correct me. Smiley
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mreich
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« Reply #9 on: June 17, 2013, 12:42:22 PM »

I think we're mainly using different terms, and I'm not even sure exactly what's right.

I use "critical" and "non-magnetic" interchangeably, because that's a specific temperature.

You are right that to fully harden, you have to be above non-magnetic, but I would say, "You need to quench at 50* above critical". Some may say you need to be 100* above non-magnetic, but then you would be using "critical" to personally describe different temperatures.

When speaking of other operations, "critical" still means a specific temp. For instance, I would not want to normalize above non-magnetic, so I'd just say "Bring it to critical and cool in still air".

Other folks may see it your way too. I'm really not sure if I'm right on this, but you hear things like "above or below critical". To me that's referring to something tangible, ergo, non-magnetic.

To complicate matters, industry often uses different temps than bladesmiths. As bladesmith's, we are looking for the lowest temp at which the steel changes from one form to the next. Industry uses temps that are usually higher, because they aren't as worried about refining the grain, they want ductility to ease manufacturing.

JMHO. I'm certainly not a metallurgist.
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chad2
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« Reply #10 on: June 17, 2013, 01:21:27 PM »

I think we're mainly using different terms, and I'm not even sure exactly what's right.

I use "critical" and "non-magnetic" interchangeably, because that's a specific temperature.

You are right that to fully harden, you have to be above non-magnetic, but I would say, "You need to quench at 50* above critical". Some may say you need to be 100* above non-magnetic, but then you would be using "critical" to personally describe different temperatures.

When speaking of other operations, "critical" still means a specific temp. For instance, I would not want to normalize above non-magnetic, so I'd just say "Bring it to critical and cool in still air".

Other folks may see it your way too. I'm really not sure if I'm right on this, but you hear things like "above or below critical". To me that's referring to something tangible, ergo, non-magnetic.

To complicate matters, industry often uses different temps than bladesmiths. As bladesmith's, we are looking for the lowest temp at which the steel changes from one form to the next. Industry uses temps that are usually higher, because they aren't as worried about refining the grain, they want ductility to ease manufacturing.

JMHO. I'm certainly not a metallurgist.

Yes agree bladesmiths temperatures are different then manufacturers temps. Sometimes higher, sometimes lower. In our case yes we want to be as low as possible, and if I was using a better oil then canola oil (aka) texaco. I would be able to bring my hardening temp down. I know that you are talking about my normalizing temp and if I had heard or read of a different temp to normalize at I would have. I get all of my temps from kevin cashen's website and from talking to numerous other knife makers that have given me these specs. Now I would use ed fowlers temperatures but I use a kiln for everything he uses a torch and a magnet. Smiley please shed some light for me if I could improve my heat treat.
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chad2
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« Reply #11 on: June 17, 2013, 03:01:18 PM »

I think we're mainly using different terms, and I'm not even sure exactly what's right.

I use "critical" and "non-magnetic" interchangeably, because that's a specific temperature.

You are right that to fully harden, you have to be above non-magnetic, but I would say, "You need to quench at 50* above critical". Some may say you need to be 100* above non-magnetic, but then you would be using "critical" to personally describe different temperatures.

When speaking of other operations, "critical" still means a specific temp. For instance, I would not want to normalize above non-magnetic, so I'd just say "Bring it to critical and cool in still air".

Other folks may see it your way too. I'm really not sure if I'm right on this, but you hear things like "above or below critical". To me that's referring to something tangible, ergo, non-magnetic.

To complicate matters, industry often uses different temps than bladesmiths. As bladesmith's, we are looking for the lowest temp at which the steel changes from one form to the next. Industry uses temps that are usually higher, because they aren't as worried about refining the grain, they want ductility to ease manufacturing.

JMHO. I'm certainly not a metallurgist.

I just want say it is very nice to have some good conversations going on. I was getting a little worn out on bladeforums.com.

Thanks mreich for sharing some good tip. Hopefully we can get some more ppl that are a lot more knowledgeable then I am in here.
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Joe Calton
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« Reply #12 on: June 17, 2013, 07:51:10 PM »

heres how I set the temp on my new homebuilt kiln. I don't know how else to calibrate it, and this method is based on listening to the steel and letting it tell you what it wants. which I think is much more accurate than any other calibration method.

get some scraps of the steel you want to heat for the hardening

bring kiln up to about 1300 or so on your indicator reading

place scrap in kiln and let it stay there for about 10 minutes, this is to allow the steel to come up to the temp inside the kiln.

open the door and stick a long handled magnet in to touch the steel

work the kiln up, 10-20 degrees at a time until the steel reaches nonmagnetic.

starting at nonmagnetic, quench the steel in your quenchant, let it cool, then file check it and break it and see what the grain looks like

go up 10 degrees at a time, breaking samples each time and checking grain. when the grain starts to appear bigger, back off back to where the grain was at its finest, and you have your baseline temp for hardening

take a fresh piece of steel, and do another quench or two or 3, with it as the first piece will likely have been through a lot of cycles to double check that you have the correct temp.




The nice thing about doing it this way is that it takes a lot of variables into account and cancels them out {variation between thermocouple and actual temp, temp loss between the kiln and the quench, ect...}. whatever the readout,that is your temp, as long as your readout is the same each time, and nothing has changed with the kiln, and your blades still meet your testing requirements, then you are golden. Even if I bought a new kiln from one of the major manufacturers, I would still calibrate it like this to each steel that I used the kiln to heat for the quench for.

The steel will never lie to you if you listen to it and give it what it wants!
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Joe Calton
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« Reply #13 on: June 17, 2013, 08:01:39 PM »

multiple quench works for stock removal also. I just got back from Ed's where we tested 3 knives I made from stock removal 52100, one was single quenched, one double and one triple.

I don't have my notes handy, but we tested them for cut, edge flex, and then broke them to see what the grain looked like.

these were from 3/16' flat 52100, and they showed a nice gain in performance from the single to the triple quench, and then when we broke them, the difference in grain size was obvious between all three.

they were also heat treated in the kiln using the method of calibration for the kiln I wrote in my last post.

I haven't ever worked with stock removal 5160, but I have with flat stock 52100, and 1095, and the multiple quench works nicely on both of those, and I would expect that it would also do the same for stock removal 5160.
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mreich
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« Reply #14 on: June 17, 2013, 08:25:26 PM »

Great post Joe!

You're welcome Chad, but don't worry, I like to talk about making knives. 99.99% of the rest of the people... not so much.

Laying your blade up against the coil would surely have a negative impact. I usually make a batch of knives, and I never put my blades into a cold oven. The concentrated heat from the blazing hot coils overheats the steel. Ramping up slowly doesn't help. I let the oven soak at temp for 15 minutes, and I arrange my blades in an arrowhead formation so they heat as evenly as possible.

I believe I get a crisp line with the torch because there is an exact temperature at which the steel hardens. I can't make a distinct line with the torch. I heat it until however much of the blade is the right color, but the color doesn't form a line. It transitions seamlessly from bright red to a little less bright, to red, etc. When I quench, the line forms from where the steel is "critical" to just barely Not critical. It's obviously a very specific temperature, because the part that was exactly the right temperature hardens, and the area that was a few degrees cooler doesn't.

Any number of variables could make a difference between your shop and mine, or who knows what Kevin is talking about. That's why it's important to figure it out for your self, and Joe did a great job of explaining the process.
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