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Theodore An.

5160-52100 differentially water quenched..

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Inspired from the work of Mastersmith Jerry Fisk I tryed something new for me..

Differentially water quench 5160 and 52100 hand forged blades..

 

https://www.youtube.com/watch?v=HEsVS5kaHtU

All went perfect !

Just after quench

26100628808_7508e669d2_z.jpg20180129_194319 by theodore Anastoulis, on Flickr25102894507_4d6c26c338_c.jpg20180129_194401 by theodore Anastoulis, on Flickr

 

After 1500 grit and a 1 minute in pcb..

28230519389_da538799b3_c.jpg20180131_212748 by theodore Anastoulis, on Flickr39977765202_6f628925d2_c.jpg20180131_212913 by theodore Anastoulis, on Flickr39977760832_1af2291c10_c.jpg20180131_213005 by theodore Anastoulis, on Flickr

 

Thank you all 

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Hate to sound discouraging, but...

While the results you got do look nice, water quenching chromium steels that benefit from a slower quench will lead to embrittlement , and hypereutectiod steels like 52100 (especially 52100) need a serious soak time to get good performance out of it.

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1 hour ago, Collin Miller said:

Hate to sound discouraging, but...

While the results you got do look nice, water quenching chromium steels that benefit from a slower quench will lead to embrittlement , and hypereutectiod steels like 52100 (especially 52100) need a serious soak time to get good performance out of it.

I don't usually tell people this because too many noobs get the wrong idea, but IF you know what you're doing well enough you can water quench 52100 and 5160.  In fact, I know a guy whose heating recipe for 52100 is so precise he HAS to water quench it to get good hardness.  He learned from the abovementioned Jerry Fisk.

The secret, such as it is, is thermal cycling.  Not just normalization, but much cycling across critical.  Lynn (Landrum, the guy I know who does this) wanted to see what kind of grain size he was getting.  The lab said "our scale doesn't go any finer than 10, and this is much smaller.  Call it 13 or 14, and how did you do that?"  You must have very precise heat controls to do this, and I don't know the exact cycling recipe.  But yes, it is possible.

I still wouldn't suggest you try it, though.  ;)

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6 hours ago, Alan Longmire said:

 

The secret, such as it is, is thermal cycling.  Not just normalization, but much cycling across critical.  

Thank you Alan

After forging did 4 stress releiving cycles from non magnetic to room temperature with my propane forge..

Next with my Eveheat kiln  i heat to 1560F/850C hold for 10 min then cool to above 1000f in room air

Heat to 1470F/800C hold for 10 min- cool below 1000F in room air

Heat to 1380F/750C hold there for 10 min-cool to below 1000f again in air

Heat again to 1290F/700C hold there for 10 min-cool to below 1000F in air

and last cycle heat to 1200F/650C hold there for 1 hour then cool to room temprerature

Grinds like butter with this process

After grinding again i heat to 1200F for 1 hour and cool to room temperature

That's my heat treating process pretty much for all my blades of all steels..

The same I did for these blades above 

Water temperature was about 170F/80C  and the temperature of the edge was barely at...well maybe 50F above critical

That's all my info 

I will put some handles on these blades and I will do some cutting tests.If they pass the tests i will do a bending test at a vise..Next I will break

them to see the grain size...I will post a video for all of you to discuss

Thank you all for all of these years of Knowledge...I've learned soooo much just reading you all you guys!

 

 

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Your grain size should be super small.  The use of descending temps like that is something that is recommended by Kevin Cashen and I am sure a ton more. 

I am however curious about your third normalizing step though, since it is below the critical temp.  Typically, soaks at temps below critical result in a spheroidizing anneal and have no affect on grain size since nothing is getting into solution.  (I think!  Please correct me I am wrong everyone)

Your last step of the hour soak at 1200 is the spheroidizing anneal and you are totally right, it works like butter after that.  

BTW, I loved your torch heating that thing.

Edited by Wes Detrick
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16 minutes ago, Wes Detrick said:

Typically, soaks at temps below critical result in a spheroidizing anneal and have no affect on grain size since nothing is getting into solution.  (I think!  Please correct me I am wrong everyone)

Grain growth can happen at sub-critical temperatures, though it is pretty slow.  Any time you induce stresses you get the opportunity to reduce grain size, and there is definitely stresses from the thermal expansion and contraction.  It is all pretty minimal though.  Mainly, sub critical stuff is just for stress relief and carbon diffusion (spheroidizing).  Just remember, if your carbon can move, so can your grain boundaries.  A sub-critical step like that could be helpful in reducing stresses from previous above critical step.  

In my opinion it is all overkill, but definitely is sound practice.  All the soaks are a bit on the long side, but that isn't really a quality problem, just a time/energy issue.  

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OK, so, without a proper kiln/oven just my forge and toaster oven I'm pretty much out of the running in this event. Not even really worth trying.

(Sorry, watching too much Winter Olympic coverage)

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1 hour ago, Jerrod Miller said:

Grain growth can happen at sub-critical temperatures, though it is pretty slow.  Any time you induce stresses you get the opportunity to reduce grain size, and there is definitely stresses from the thermal expansion and contraction.  It is all pretty minimal though.  Mainly, sub critical stuff is just for stress relief and carbon diffusion (spheroidizing).  Just remember, if your carbon can move, so can your grain boundaries.  A sub-critical step like that could be helpful in reducing stresses from previous above critical step.  

In my opinion it is all overkill, but definitely is sound practice.  All the soaks are a bit on the long side, but that isn't really a quality problem, just a time/energy issue.  

What kind of slow are we talking?  Is it a rate of time that our soak times don't really touch, or is there a limit in time we should watch out for? 

I was hoping you would pop up to correct my errors Jerrod :)

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Would you accept "very slow"?  If you look into Fick's Laws of Diffusion, you'll see why you don't really want to open that can of worms.  Suffice it to say that there is no reason to soak beyond the time it takes to dissolve your carbides (a few seconds to a few minutes, depending on alloy), so don't do it.  You also shouldn't heat more than you need to (note that forging and aggressive normalizations do count as "needs" for this context). 

I over simplified a bit earlier.  To expand a little:

Edit:  I recommend skipping all this reading unless you are a little crazy (like me).  Skip down to the next post where Wes found a chart that sums up this stuff pretty well.  

Atoms need a little energy to start moving around in the lattice.  This is the activation energy.  Depending on what atoms and what structure, this could be room temp or considerably higher.  Once you pass that activation energy, things just happen quicker.  This is why over heating is not good, because it makes things happen very quickly.  If you were to hold .  Interstitial (like carbon in steel) and substitutional (like Cr or Mn in Fe) diffusion are slightly different, as is moving of grain boundaries, which is a form of diffusion.  On top of that, atomic stacking plays into it.  So if you were to compare BCC at 15 degrees below critical and 5 degrees below critical, you would see a different constant once you look at BCC at 5 degrees below critical and FCC 5 degrees above critical (even though both steps are just 10 degrees).  Generally (VERY generally), the diffusion equation looks like this: 

D1 = D0 * exp(-Q/(RT))

D1 is your diffusion coefficient, D0 is your material constant (non-temperature dependent, experimentally determined), exp means exponent (so D0*e^(-Q/RT) is what is meant, and e^1 is 2.718, in the same way Pi is 3.14), Q is the activation enthalpy, R is the universal gas constant (yes, even though we aren't dealing with gases), and T is the temperature.  

For example with units, here is C in BCC Fe:

D0 = 2.0 mm^2/sec,  Q = 84.1kJ/mol,  R = 8.314 J/mol K (that is degrees Kelvin)

You would look up D0 and Q for your given situation (e.g. C in BCC Fe).  Which is what I did for the above example.  If we wanted to look up C in FCC Fe, the numbers would be different.  

None of that is necessary to worry about with bladesmithing.  It is all very much overkill.  You should be able to do everything you need for normalizing and hardening by watching for decalescence and recalescence and counting off seconds in your head (or look at a watch/clock).  

I know you are sorry you asked.  I forgive you.  You didn't know better.  Please let this be a lesson for the future.  ;)

Edited by Jerrod Miller
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29 minutes ago, Jerrod Miller said:

I know you are sorry you asked.  I forgive you.  You didn't know better.  Please let this be a lesson for the future.  ;)

I am not sorry I asked, just a nice reminder that asking why is sometimes a perilous adventure . The math doesn't intimidate me and I understand your explanation.  
And I will totally take very slowly for an answer.   Although I did a google search for diffusion of carbon into iron and found this chart, which was a nice visualization of what you were talking about.  At forging temp and above (>= 1000C), it diffuses pretty quickly; not so much at 600 C. (That is, if I am reading this graph right :D )

 

Capture.PNG

 

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1 hour ago, Jerrod Miller said:

 

I know you are sorry you asked.  I forgive you.  You didn't know better.  Please let this be a lesson for the future.  ;)

 Well after reading all that I feel about as educated as a roll of biscuit dough..... thank you so much for the explanation, I'm going to go take a few Tylenol and see if I can't recover. 

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17 minutes ago, Wes Detrick said:

That is, if I am reading this graph right :D

You are, and that chart is a fantastic aid to my rambling "explanation".  I'll make a note in my post above to let people know they should skip the words and go straight to your chart.  

Though a bit of warning:  It goes quicker, but not super quick.  Damascus evens out carbon content pretty well for 2 reasons: 1) you spend quite a bit of time at very high temperatures, and 2) your layers get pretty thin so it doesn't have to move too far to get an even distribution.  Case hardening something like a gear (or a blade blank for that matter) takes MUCH longer than you would think to get to an effective depth.  

Also, be aware that interstitial diffusion of C, as noted on that chart, is MUCH faster than substitutional diffusion.  So grain growth is slower than carbon diffusion.  

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17 minutes ago, Jerrod Miller said:

Also, be aware that interstitial diffusion of C, as noted on that chart, is MUCH faster than substitutional diffusion.  So grain growth is slower than carbon diffusion.  

Ohhhh, I am glad you added that.  I was unsure what it meant by substitutional diffusion.  Wow, that is quite slow compared to carbon diffusion.  

So at 1000C the grain will only grow at about 10^-12 m^2/s?  But that makes sense, otherwise grain would be HUGE after a short period of time.  I have a piece of steel laying about somewhere that was in my buddies forge for god knows how long.  Multiple multiple forging sessions (his full time gig is as a blacksmith) and you can see the crystals are huge in it.  

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I do love a good explanation.  Thanks!

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Μr Jerrod Miller and Mr Wes Detrick,thank you for all the explanation!

This forum is really a River of Knowledge!Thank you all.much appreciated!

 

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My pleasure, although Jerrod did all of the heavy lifting :)

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12 hours ago, Wes Detrick said:

heavy lifting

Nah, the book I used for reference only weighs a couple pounds (Amazon says 9.6 oz, and I don't have a scale in my office, but I'd say more like 2 pounds).  ;)

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6 hours ago, Jerrod Miller said:

Nah, the book I used for reference only weighs a couple pounds (Amazon says 9.6 oz, and I don't have a scale in my office, but I'd say more like 2 pounds).  ;)

YO!  The hardcover version of that book is $3210.80!  I hope you have the hardcover version my friend, because that will buy you some great tools.

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2 minutes ago, Wes Detrick said:

YO!  The hardcover version of that book is $3210.80!  I hope you have the hardcover version my friend, because that will buy you some great tools.

I'm planning on building a shop (with living quarters) this summer, so if I had the hardcover I would certainly sell it and fund the shop!  I'd even sell it for $3k and offer free shipping.  But sadly, mine's paperback. 

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