Heat Treatment - Crystal Weaving Foundation

Thanks Cobalt.
That 61rc D2 blade looks tough. Worse part of edge deformation reached to about edge shoulder thick. From reflection, I guess, edge angle is about 22-25dps. Your recall/guess? There is a large chip on spine due to poor hammer strike, chip perimeter has sharp edges, which indicate low plasticity. So would batoning - with hammer - to a granite rock be a good test? because it would yield similar edge damages.
When testing, it is good to have external point of references/baselines. Next time doing D2, I can target for 61rc and try to replicate this test. Please do advise/guess/suggest on parity of edge geometry.
 
Bluntcut, I found a link that described what happened to the knife. The knife was placed on an anvil and then hit with a hammer for what they claim to be 1.5 hours. My guess is they meant 1.5 minutes. Probably a typo no one caught. The edge was between 61 and 62 Rc. Here is the link:

https://www.bladeforums.com/threads/d2-torture-testing-cool-pics.322561/

They also discuss cryo in there and it is misleading because it is a small part of their HT.

As for edge geometry, those were thin slicers. I had one. I would guess you are probably correct as to edge angle. Between 20 and 25 dps. The edge on mine would go for a long time and I dropped the angle down to 15dps, which is what I use on all my knives. But I never took a hammer to mine.
 
Curious that the spine chipped -- two or three large chips -- while the edge just flattened.

The edge doesn't look like it was hitting an anvil, but rather something like a nail. Unless the edge was hammered against a corner of the anvil.



Cobalt said:
JyKAI0A.jpg

The edge
kSd9Kqx.jpg
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From what they wrote. The spine was against the anvil and the hammer hit the edge.
 
Look like a bunch of gentle hammer hits onto edge because a few big hits would shows large smooth flattened sections. OK, this should be easier than batoning a granite or common rock.

Cobalt said:
From what they wrote. The spine was against the anvil and the hammer hit the edge.
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The edge looks too jagged to be hit by a hammer. I wonder if the edge wasn't chipping and then being flattened as the edge lost material.

Also, you can see a large chip on the left side of the spine, within the clip point, that shouldn't have been in contact with the anvil.

I have a low-quality Randall that I can hammer. It's steel is very soft, however. But maybe we can learn something.


kSd9Kqx.jpg
 
I think there was more damage pics but many re gone. There was a string of pics about 5 or 6. One showed the entire knife. But they are gone now.

Eric Isaacson said:
At this point, when the picture was taken, the edge was undamaged (uncracked) and the blade would return to true. We did continue to bend it to destruction and at that point the blade had taken a set, which in itself is unbelievable because D2 normally will not take a set but will just break(and break with very little bend).

I hope this helps
:D:D
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Eric Isaacson said:
Actually we are not just saying that's what we did we are actually showing you we did it in the pictures that are posted. That's one reason we post the pics, a lot of people can say there knives perform, few actually show you that they do.


The face of the hammer! The spine of the knife was placed on the anvil with the edge up. Then the edge was pounded with the face of the hammer. I hope that helps.

:D:D
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Hammer blows to Randall's soft steel looks much different. As Luong says, you can see the flat areas from the hammer strikes. I hit the edge fairly gently -- like pounding a small finishing nail -- and the edge just collapsed. The edge flattened and smeared. The spine had no damage. This is a very tough, very soft steel. Not much to it.

2v2EaTMWWxAWtWs.jpg

2v2EaTMQLxAWtWs.jpg

2v2EaTMtWxAWtWs.jpg
 
Twindog, don't do that to a nice Randall. Not worth it. The edge damage to the knife above is typical of what I have seen from tough steels. The edge will mash to a point and after that, it does not deform much anymore. It just crushes in. At some point it will fracture through causing blade failure. The important aspect is the mashing at Rc 61-62. No chipping.
 
Thanks for the concern, Cobalt. But I had already ruined this Randall. The fit and finish was really poor (look at the quality of the jumping), and when I tested the steel, it was so soft it felt like it was made of lead.

2v2JTYgcVxAWtWs.jpg

2v2JVnWUSxAWtWs.jpg
 
Twindog, the damage in your picture is not the damage I have seen from a tough steel. It is damage I have seen from a weak ductile steel. Makes sense. Bad HT or no HT, lol

Hard to believe Randall let that one out. I guess everyone can have a bad one slip out once in a while. Hopefully not to often
 
Bluntcut, testing on D2 and ATS34 would be interesting with your method. Getting toughness out of steels that normally do not have it, is a good way to see if your system really works. 440C, ATS34, D2, 154cm etc.
 
Twindog - Thanks for destruction test that Randal knife. Damages on that blade, indicated: it didn't hardened past 50rc and sad smushy brittle cookies edge. I will look into a replacement bcmw d2 knife for you.
 
Agree. 440C/N695 is in next test set. I don't have 154cm but oh well, will settle with higher quality cpm154. It might also be in the next test set. Will/would target for 63rc and 64rc respectively.

Cobalt said:
Bluntcut, testing on D2 and ATS34 would be interesting with your method. Getting toughness out of steels that normally do not have it, is a good way to see if your system really works. 440C, ATS34, D2, 154cm etc.
Click to expand...
 
Bluntcut, the test I have used to test if a knife fails is the cement nail test. Cement nails are 3/8" thick and very tough. They form a literal C-notch in the blade and is a good way to see when and if the blade fails. Here is an example of one knife I did.

MC7NCjS.jpg

JQm2bg4.jpg
MuVR3J9.jpg
 
Sure, it would be informative to try ATS34 (perhaps better version of ingot 154cm). I can provide address via pm or email bcmw flexbiz com. Thanks.
I would target ats34 for 63rc. I know these hrc a bit on high side, however high hrc = bigger amplitude of toughness deltas and easy to detect plasticity threshold.
Further more, 440C ESR should be cleaner stock, maybe close or better than ats34.

Cobalt said:
I may have an old ATS34 blade for you to play with. No handles. I will look for it if you want to try it.
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That is a brutal ductility test. Main objective of my nail shock tests is to observe strength and amount of plasticity. In my perspective, ductility = ferritic displacement and accompany by low hrc, plasticity = temperred martensite displacement and hrc 58-68. Ductile steel can work hardened and necking toward stretching limit, vs tempered martensite would work-harden quicker (pile up) and necking in 5-20% range depend on ferrite% in mart matrix.

Good concrete nail is around 45-47rc along of massive bulk (circle cross section), blade+edge need bulk up. Getting a 'C' on edge = smushed in = ductile. Getting a combination of wavy and side-deflection and some small rolls = deformation = plasticity inverse proportional to strength. This type of ductility tests maybe more useful for high strength structural and armor steels.

Cobalt said:
Bluntcut, the test I have used to test if a knife fails is the cement nail test. Cement nails are 3/8" thick and very tough. They form a literal C-notch in the blade and is a good way to see when and if the blade fails. Here is an example of one knife I did...
Click to expand...
 
bluntcut said:
Sure, it would be informative to try ATS34 (perhaps better version of ingot 154cm). I can provide address via pm or email bcmw flexbiz com. Thanks.
I would target ats34 for 63rc. I know these hrc a bit on high side, however high hrc = bigger amplitude of toughness deltas and easy to detect plasticity threshold.
Further more, 440C ESR should be cleaner stock, maybe close or better than ats34.



That is a brutal ductility test. Main objective of my nail shock tests is to observe strength and amount of plasticity. In my perspective, ductility = ferritic displacement and accompany by low hrc, plasticity = temperred martensite displacement and hrc 58-68. Ductile steel can work hardened and necking toward stretching limit, vs tempered martensite would work-harden quicker (pile up) and necking in 5-20% range depend on ferrite% in mart matrix.

Good concrete nail is around 45-47rc along of massive bulk (circle cross section), blade+edge need bulk up. Getting a 'C' on edge = smushed in = ductile. Getting a combination of wavy and side-deflection and some small rolls = deformation = plasticity inverse proportional to strength. This type of ductility tests maybe more useful for high strength structural and armor steels.
Click to expand...

Good point. It may be to much for steels like ats or D2.

I did it on 1095 by kabar, 3V by Carothers and INFI. Here is 3V by Carothers:

Then INFI:
 
I remember these 2 videos (and also the 3V with Nathan's Delta HT). However I can't recall these blades specs and edge geometry. Would appreciate a refresh + closeup pics of edge and nail if you still have them.

The chopping block played a big role in these video, it absorb and rebounce every hammer strikes. In consequence the impulse is greatly lower because F = MA, where A(is lower) transfer impulse onto spine, edge into nail, nail into wood <= this part provide travel distance = more time, hence impulse is lower. Your tests are valid and brutal :thumbsup:. I am just wishing not having the chopping block variable too involved.
 
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