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Have a knife made from 5160. Going to be using a furnace, plus anti scale compound for the heat treat. The Heat Treaters Guide say's to normalize at 1600 F, and austenize at 1525 F. I know this book is talking about larger sections then knife blades. Does anyone disagree with these temps? If so, what temps do you recomend for a triple normalizing, and then austenizing? Thank you. :notworthy: :wacko:

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Those are the temps my books show as lows Tony. I usually bump it up to 1550 for heat treat on 5160. The book actually shows 1525 as low end and 1600 as high end for heat treat.

Crocker Knives

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You're doing a triple normalize in an attempt to reduce grain size so you shouldn't exceed 1525 for either normalize or hardening.soak 7-8 minutes at temperature.

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Have a knife made from 5160. Going to be using a furnace, plus anti scale compound for the heat treat. The Heat Treaters Guide say's to normalize at 1600 F, and austenize at 1525 F. I know this book is talking about larger sections then knife blades. Does anyone disagree with these temps? If so, what temps do you recomend for a triple normalizing, and then austenizing? Thank you. :notworthy: :wacko:

 

You know I keep running in to things that dont quite agree with info. in my books. Im not sayin the books are wrong but how do you know for sure exactly what the steel is yea it might be 5160 but is it from the same batch the guy in the book checked ? could maybe the alloys be a smige different ? say even where you have got the steel from maybe could have been a mix up and really not 5160? using salavge steel are you sure its 5160?

Like I say I guess I was lucky and noticed my non magnet temps. were way off from what the books say thinking I had 5160.

From now on first thing Im doing is check with a magnet & temp. probe - watch my shadows to know my lower temps and higher temps just double check things.

Im still learning

maybe someone with more know how will help out

Ron

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Well METE is the man for metallurgy. At 1525 the blades don't reliably harden for me. I have had similar problems with 10xx steels. I bumped it up 25 degrees and no more problems. I talked to the local heat treat shop and they do 5160 at 1550 also. I think there will be a little variability with equipment and individual processes. I guess all I can really say is it works for me with my equipment.

Edited by Tim Crocker

Crocker Knives

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Tim, that's why it's always best to experiment .Learn exactly what's best for your methods and equipment . Lots of blade makers use the 1525 F but if it doesn't work for you then by all means go up to 1550F ! :rolleyes:

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mete

 

Im trin to learn

 

 

reducing grain size

Now the 3 normalizing cycles stay on the cool side of non mag.

then aneal but stay below critcal hold above 1000 for 2 hours

and cool slowly to room temp.

With the triple hardening you are further reduceing the grain

just hitting non mag. and into the quench until temp. of oil

remove cool to room temp. repeat 2 more times.

 

Rather than heating to non mag. and soaking to get screaming hardness,

would it be better to not be so sever with the hardening and doing 3 cycles with less stress?

So you have an tougher blade thats not so brittle thats been through less stress

finer grain thats easier to sharpen and cuts longer? I know it needs tempering but isnt less stress better?

 

Is this wrong ?

Ron

 

The reason I asking is:

My last knife 5160 I heated almost 1600 and quenched

it was screaming hard so hard the steel at the edge contracted so much it pulled the

tip down a good 1/4 in. I tempered at 350 for 3 - 1 hour cycles { maybe I should have done 3-2 hour cycles}

Its a bear to sharpen its tough and holds a edge well though.

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I have been playing with my 5160 heat treat a bit the last few days as well and was reminded of a few things....1550f is a perfect all around temp. for austenitizing 5160. My personal experience is that if you soak for a bit to get everything into solution 5160 gets way hard at anywhere from 1450f to well over 1600f with very little grain growth. The chromium really does a great job of limiting grain growth at elevated temps. But some 5160 runs a little low (.8 or less) and .2% difference in chromium content can change stuff quite a bit. I have deliberately quenched 5160 test bars at temps up to where the steel is just plain yellow in color and the broken bars still have very fine grain structure.

 

I'd bet that fully hardened 5160 that has been tempered at 350f for three one hour cycles is still very close to Rc60+ and probably *is* a bear to sharpen but would hold an edge for an insanely long time....probably a little chippy and prone to breaking in a long blade at this hardness, IMO.

 

I temper 5160 at 425f- 450f (2 or 3 one hour cycles in molten salt) and end up at around Rc57-58 and they are so tough they laugh at bending/break tests at this hardness and still hold an edge for a very long time.

 

Series of three works great for me...3 normalization cycles and 3 temper cycles. It's aweful tough to screw up 5160 that is clean and has chemistry within tolerances in my experience. But watch the chromium content if you buy 5160 and be suspicious of it if it is salvage. My personal feeling is that the difference between 5160 that is .56% carbon and has less than .8% chromium and steel that has very near the full .6% carbon and a 1% chromium can be pretty severe when it comes to heat treat and final hardness, grain size and all that. "Cheap" 5160 or stuff where the chemistry was fine for making springs or whatever can be a far cry from something like 5160H where the steel is virtually tool steel quality in terms of being on spec. for alloying elements. The ideal is .6% carbon and 1% chromium and very little of the 5160 steel I had tested for chemistry was actually that rich in carbon and some was so low in chromium that there was actually more manganese present than chromium.

 

Brian

"Imagination is more important than knowledge" - Albert Einstein

 

"The innovator is not an opponent of the old. He is a proponent of the new."

- Lyle E. Schaller

 

http://home.mchsi.com/~hermits/BrianRVanSp..._Edged_Art.html

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Tough and holds and edge well ? I thought that was what a knife was supposed to be. :) I see no point in annealing after normalizing. I would also normalize no more than twice. The point of triple hardening is to refine grain it doesn't have to do with stress.

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Tough and holds and edge well ? I thought that was what a knife was supposed to be. :) I see no point in annealing after normalizing. I would also normalize no more than twice. The point of triple hardening is to refine grain it doesn't have to do with stress.

It doesnt help the grain size anealing after normalizing only making it soft.

I thought Ed Fowler Anealed ? maybe Im reading it worng?

So If I anealed ( I use files no grinder ) should I repeat the 3 normalizing cycles

then 3 harding cycles?

I only heated to 1325 when I anealed

( in a pipe with 10lbs charcoal on top 1325 temp. for 2 hours- 2 hours latter temp. droped to 1275

- next morning temp 930) I think that is close I did it last week should have taken notes.

Could this Normlized the blade as well as Anealing?

This was the softest I had ever gotten a blade-it worked great with files.

 

I have a little more sanding to do, just about ready to harden.

 

Thanks for your help

Ron

Edited by Ron Hicks
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Ron, after you forge you normalize to remove stresses and make the grain uniform size throughout the piece. You will have a structure of pearlite .Annealing pearlite [your subcritical anneal] will do nothing to it. If you are using files[usually W-1 or W-2] then you should anneal , above critical and slow cool in ashes .Then proceed to grind , then normalize to get rid of the grinding stresses. [ When asking questions about proceedures please give details for that material only,lesss confusing that way. Material , forging , normalizing annealing etc. ( I'm confused enough today ;) ]

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Sorry mete

I anealed it so I could work it with files- the steel Im not sure its an old Leaf Spring maybe Ford ?2 ton

truck

it goes nonmang at about 1425.

I have it ready to harden I will normlize it again then harden in veg oil heated to 150

3 times.

Temper at 400 3 times

Ill use my magnet & see what happens

sorry for buggin you

Ron

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Tim, that's why it's always best to experiment .Learn exactly what's best for your methods and equipment . Lots of blade makers use the 1525 F but if it doesn't work for you then by all means go up to 1550F ! :rolleyes:

 

 

O.K. so, my blade is forged, slow cool anealed in vermiculite, ground, and hand sanded to 400 grit. Now, I should normalize two or three times at 1525 F, soaking for 7 to 8 min each time. If I've normalized 3 times to reduce grain size, is there really any reason to do a triple hardening quench ? Haven't I already reduced the grain size enough? Wouldn't I just be stressing the blade unnecessarly with the additional quench's?

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This question is for Mete, whose opinion I would highly respect.

And, I know this thread is bouncing from one wall back to the next, but I had to ask anyway!

(It'll give you more computer time, Mete!) I know you love it!

After forging, and normalizing, (somewhere between 2 and 19 times!), forging scale has been cleaned up and the blade shape/profile/etc. cleaned up, does a sub-critical spherodizing anneal, (1375-80 for an hour or so and then ramp down at 10 degrees/hr to about 1200) help pool the carbides evenly throughout the blade and thus sort of "set-up" the blade for hardening?

I'm forging my blades down from 1" square stock, which is a long way to go down to a 1/4" blade, and feel that this sperodizing anneal would help to make "all things equal" throughout the blade.

I have been lead to believe by more than a few individuals who you are familiar with, that this is not only correct, but preferred with something like 5160 when forging down from large stock.

This of course would require a controlled heat treating furnace, which I use.

I would respect your opinion.

 

 

 

 

 

Ron, after you forge you normalize to remove stresses and make the grain uniform size throughout the piece. You will have a structure of pearlite .Annealing pearlite [your subcritical anneal] will do nothing to it. If you are using files[usually W-1 or W-2] then you should anneal , above critical and slow cool in ashes .Then proceed to grind , then normalize to get rid of the grinding stresses. [ When asking questions about proceedures please give details for that material only,lesss confusing that way. Material , forging , normalizing annealing etc. ( I'm confused enough today ;) ]

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mete

I also would respect your opinion on the sub-critical spherodizing aneal.

 

Sorry for the confusion but I did not have the experence

or smarts to make it clear.

 

Ron

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By the way, Brian, I have 1" square 5160 that is .61% C. and .71% Cr. How do you think that rates?

 

 

 

 

I have been playing with my 5160 heat treat a bit the last few days as well and was reminded of a few things....1550f is a perfect all around temp. for austenitizing 5160. My personal experience is that if you soak for a bit to get everything into solution 5160 gets way hard at anywhere from 1450f to well over 1600f with very little grain growth. The chromium really does a great job of limiting grain growth at elevated temps. But some 5160 runs a little low (.8 or less) and .2% difference in chromium content can change stuff quite a bit. I have deliberately quenched 5160 test bars at temps up to where the steel is just plain yellow in color and the broken bars still have very fine grain structure.

 

I'd bet that fully hardened 5160 that has been tempered at 350f for three one hour cycles is still very close to Rc60+ and probably *is* a bear to sharpen but would hold an edge for an insanely long time....probably a little chippy and prone to breaking in a long blade at this hardness, IMO.

 

I temper 5160 at 425f- 450f (2 or 3 one hour cycles in molten salt) and end up at around Rc57-58 and they are so tough they laugh at bending/break tests at this hardness and still hold an edge for a very long time.

 

Series of three works great for me...3 normalization cycles and 3 temper cycles. It's aweful tough to screw up 5160 that is clean and has chemistry within tolerances in my experience. But watch the chromium content if you buy 5160 and be suspicious of it if it is salvage. My personal feeling is that the difference between 5160 that is .56% carbon and has less than .8% chromium and steel that has very near the full .6% carbon and a 1% chromium can be pretty severe when it comes to heat treat and final hardness, grain size and all that. "Cheap" 5160 or stuff where the chemistry was fine for making springs or whatever can be a far cry from something like 5160H where the steel is virtually tool steel quality in terms of being on spec. for alloying elements. The ideal is .6% carbon and 1% chromium and very little of the 5160 steel I had tested for chemistry was actually that rich in carbon and some was so low in chromium that there was actually more manganese present than chromium.

 

Brian

Edited by kbaknife
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Ron, If you want to stress reieve yourself ,soak in a hot tub for 1 hour. <_< .....Normalizing removes stresses, refines grain, and makes grain uniform throughout the piece [" all things equal"]. If you are going to refine grain by hardening three times it doesn't make sense to normalize more than once .BTW the longer the steel is above the critical the more scale and decarb you will have ! Depending on the steel and the cooling rate the anneal will produce fine or coarse pearlite or fine or coarse spheroidized structure . The most uniform structure and easiest to subsequently heat treat is to start out with martensite which is then sub-crtically annealed . This results in a fine spheroidized annealed structure....Kbaknife, after subcritical anneal there's no reason to ramp down as no further changes will occur if air cooled from the anneal.

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Thank you.

That makes some sense.

 

 

 

 

....Kbaknife, after subcritical anneal there's no reason to ramp down as no further changes will occur if air cooled from the anneal.

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Ron, If you want to stress reieve yourself ,soak in a hot tub for 1 hour. <_< .....Normalizing removes stresses, refines grain, and makes grain uniform throughout the piece [" all things equal"]. If you are going to refine grain by hardening three times it doesn't make sense to normalize more than once .BTW the longer the steel is above the critical the more scale and decarb you will have ! Depending on the steel and the cooling rate the anneal will produce fine or coarse pearlite or fine or coarse spheroidized structure . The most uniform structure and easiest to subsequently heat treat is to start out with martensite which is then sub-crtically annealed . This results in a fine spheroidized annealed structure....Kbaknife, after subcritical anneal there's no reason to ramp down as no further changes will occur if air cooled from the anneal.

mete

Thanks for the reply- Im sure this is just plain simple for you but

I do not have the experence and wanting to understand whats going

on with heat treat.

I understand what I need to do

you did not waste your time

I did get a fine blade out of all this :)

Thanks

Ron

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There a couple of really good simple texts on heat treating - one book is ASM Practical Guide to Heat Treating...Another book on quenching that is simple and practical, and gives a bunch of Why and wherefors of quenching is Houghton on QUenching - it is a freebie. Do a search and it is posted somewhere on the site.

 

Scott, aka KB0FHP

D. Scott MacKenzie, PhD

Heat Treating (Aluminum and Steel)

Quenching (Water, Polymer, Oil, Salt and Mar-Tempering)

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By the way, Brian, I have 1" square 5160 that is .61% C. and .71% Cr. How do you think that rates?

 

I'd say that would make a damn fine knife. :D

 

I had a buddy who was using salvage steel (some kind of suspension spring from a vehicle) and simply could not get the stuff as hard/tough as I was getting mine using the same techniques. Hell, he was using my shop to heat treat it!! :261:

 

After playing and guessing and cursing and all that stuff he sent it of to a friend of ours who works at a local factory and has access to lab and steel chemistry testing. After a long wait we find that the steel had less than .5% carbon and and about an equal amount of chromium. I buy all my steel new and haven't had the occasion (or need) to have its chemistry verified in the last 10 years but the stuff I had from the same vendor a decade ago was tested by the same guy and facillities at .6% carbon and .75% chromium.

 

I can't keep this stuff from getting hard as hell...even if heated with a torch to "what ever temp. looks good" and quenching into anything from used motor oil/kerosene to molten salt it gets roaring hard and is unbelievably tough after tempering.

 

I don't really wanna get into a discussion about chemistry and what is good, better, or best 'cause I'm not qualified. I just wanted to make the point that even very small and seemingly insignificant differences in carbon content and chromium can have some pretty drastic effects. I'm no expert but my experience and empirical testing tells me that chromium acts like a kind of multiplier in accordance with carbon content and that even a very small variance of chromium can effect a lot of the hardening characteristics of "5160". It seems much more powerful (chromium) than carbon is in hypoeutectoid steel in promoting carbide formation and deep hardening while keeping grain size very small and promoting toughness.

 

Even in steel that is abused or heat treated by morons like me. B)

 

I am always amazed that guys have so much trouble getting great results out of 5160. Normalize it 3 times at a good salmon color in a dark room (about 1550) and harden it at the same color by quenching into "some kind of oil" that gets it below incandescent

in about 6 seconds or less (but not water) an and then temper it a couple times for an hour at 450f. You can get fancier but 5160 is pretty much designed to be heat treated with minimal fuss and is not in the least bit finicky in my experience. It's like O1. The only way to screw it up is to quench it way too low or so fast it cracks. Didn't get what you want? Just normalize it again and try again.

 

My opinions.

 

Brian

Edited by Brian Vanspeybroeck

"Imagination is more important than knowledge" - Albert Einstein

 

"The innovator is not an opponent of the old. He is a proponent of the new."

- Lyle E. Schaller

 

http://home.mchsi.com/~hermits/BrianRVanSp..._Edged_Art.html

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Brian:

 

You are right - Cr acts like a sort of multiplier to allow the steel to get harder deeper into the section. It does not cause the steel to get harder - that is governed strictly by the carbon content (the grain size plays a small part - with larger the grain the harder the steel - small grain adds toughness). The alloying elements allow a thicker section to be made with the same quench....all other things being equal.

 

Scott

D. Scott MacKenzie, PhD

Heat Treating (Aluminum and Steel)

Quenching (Water, Polymer, Oil, Salt and Mar-Tempering)

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Hey Scott,

 

Folks have told me that aside from being deep hardening, 5160 offers no advantage over plain 10XX steels with the same relative carbon content. I have not found this to be the case and feel that fully hardened and tempered 5160 seems superior in it's ability to absorb shock without permanent deformation and that it seems tougher and more abrasion resistant than plain old steel with .5 - .6 percent carbon.

 

Can the addition a chromium accout for this? Or am I just not being objective enough in my testing?

 

My impression was that the chromium was added primarily to get deeper hardening and to limit grain growth at elevated austenitizing temperatures....kind of making the steel stupid proof and less needy of having exact temperature control during austinitizing. But does the chromium actually promote carbide formation and aid toughness after tempering or is it just my fanatic love of 5160 that makes it seem this way? :lol:

 

Brian

"Imagination is more important than knowledge" - Albert Einstein

 

"The innovator is not an opponent of the old. He is a proponent of the new."

- Lyle E. Schaller

 

http://home.mchsi.com/~hermits/BrianRVanSp..._Edged_Art.html

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5160 will thru-harden in thicker sections. It also has better impact properties. The Cr will also slow down grain-growth. It will also have better secondary hardness and resist tempering - or rather it will be slower to temper. A much better steel than 1060.......

D. Scott MacKenzie, PhD

Heat Treating (Aluminum and Steel)

Quenching (Water, Polymer, Oil, Salt and Mar-Tempering)

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