Heat Treatment - Crystal Weaving Foundation

bluntcut said:
Comparing edge performance of 11 steels at 7dps in cutting 1" diameter sisal rope and bamboo chopstick.

10V 67.5rc, 15V 67rc, 26C3 65rc, D6 66.5rc, M4 65.5rc, M398 66.5rc, Magnacut 64rc, S35VN 64.5rc, S90V 65rc, T-15 66.5rc, Z-Wear 65rc.

8:28 video

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M398 seems to have done exceptionally well.

Is it that much tougher than M390?
 
353 said:
M398 seems to have done exceptionally well.

Is it that much tougher than M390?
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No, m390 should be tougher (wider plasticity range and bit more ductile) than m398. In this task performance test, M398 is on top among test knives however if rate on toughness, 26C3 is on top (I just looked with 30x loupe).

There was a 61.5rc 204P (equiv to m390) blade in this batch but it is below my 63rc cut off hardness, thus it is being re-sequencing in new batch.
 
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Twindog said:
Great stuff, Luong.

It looks as though 15V held up better than M4 or Zwear or other much tougher steels. What's your take on that performance.
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Given higher strength with full elasticity range and some plasticity. Of course plasticity occurs when beyond/yielded after limit of elasticity, logical to infer tested steels has certain amt plasticity. M398 & 15V have highest carbide volume%, which provide additional particle strengthening, thereby highest strength among tested steels.

With strength + full elasticity:

1st provide more resistance to edge deflection, i.e. take more lateral force to bend.

2nd has long bending radius - due to more volume of steel in engagement/interaction. Envision putting a load on a branch (or cantilever), low strength tip will bend more readily (thus short bending radius), hence prone to yield more readily than higher strength.

Diamond, ceramic and conventional ht at near peak hardness steels are brittle. Where these have high strength but don't have full elasticity range, where deflection yield point is narrow (far from full elasticity range), fracture zone thereafter.
 
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Let's how a straight razor edge geometry (7 degrees per side edge geometry) made out of 67rc S125V perform in cutting 1" diameter sisal rope and whittle bamboo chopstick.

6:48 video

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Comparing 2 similar wear resistance steels, tool steel vs stainless with 10dps edge geometry. Cut rope, bamboo, tap-chop 4x4, whittle pork rib bone.

K390 Tool steel knife with conventional ht at 65rc (iirc) - I made this knife at least 6 years ago.

S110V Stainless steel knife with latest research metal sequencing TF0_SBG1_3DTG15.


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Tested 63.5rc CPM 154 15" OAL Chopper. Same result as W2 chopper above - rolled edge, failed to slice phonebook paper. 64rc magnacut & 66rc 4V choppers most likely (extrapolated) will produce similar result as W2 & CPM154, hence skip this test.

65rc M398 15" OAL chopper test result

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Will test the last chopper - 67rc S125V - when ready.
 
CPM S125V 67rc

Objective: Chop 2x4 with straight razor edge (7.5 dps and no more than 20 strikes to chop through) and afterward edge still slice phonebook paper without tearing.

Result: Success

11:25 video

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Edit 10/23:
M398 65rc, 15.25" AOL, 1.15 lbs Test sequenced steel chopping - kiln dried stud 2x4 - stability & performance
 
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shqxk said:
Do you always apply full annealing before re-ht high alloy steel?
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Mostly no. I do full anneal process of high alloy when post-quench processes involved non-localized carbon diffusion transformations. For example - specimens tempered above 425F, basically higher temper temperature = more carbon diffusion in density & distance = good to reset steel to a known initial condition. Unless one/I know microstructure at hand, then one/I can perform necessary thermal steps to dissolve & re-distribute carbon in solution prior to quench. btw - Cr can diffuse but albeit very slowly compare to Carbon and affinity toward grain boundary. For this one, it is more cost effective to throw away specimens rather than do Cr normalize/thermal cycles and then a full anneal.
 
bluntcut said:
Mostly no. I do full anneal process of high alloy when post-quench processes involved non-localized carbon diffusion transformations. For example - specimens tempered above 425F, basically higher temper temperature = more carbon diffusion in density & distance = good to reset steel to a known initial condition. Unless one/I know microstructure at hand, then one/I can perform necessary thermal steps to dissolve & re-distribute carbon in solution prior to quench. btw - Cr can diffuse but albeit very slowly compare to Carbon and affinity toward grain boundary. For this one, it is more cost effective to throw away specimens rather than do Cr normalize/thermal cycles and then a full anneal.
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Can I send a couple of blades to you to re-ht? May be I will also buy some blades you made. I really want to try that unusual high hardness at low angle like what you did in those videos.
 
shqxk said:
Can I send a couple of blades to you to re-ht? May be I will also buy some blades you made. I really want to try that unusual high hardness at low angle like what you did in those videos.
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We can discuss details of sending me grounded pre-ht blades for my sequence/protocol - please email bcmw@flexbiz.com. Or more convenient asking friend/makers in the US (rather than send from Thailand) send me blades - ground certain way (to avoid warping, especially my sequence takes around 2 weeks to conduct). Thanks for considering to buy my blade but I think, since you want to assess/eval my sequence, therefore better to start with your blade and perhaps can side-to-side compare with your baseline ht-ed blade.
 
bluntcut said:
We can discuss details of sending me grounded pre-ht blades for my sequence/protocol - please email bcmw@flexbiz.com. Or more convenient asking friend/makers in the US (rather than send from Thailand) send me blades - ground certain way (to avoid warping, especially my sequence takes around 2 weeks to conduct). Thanks for considering to buy my blade but I think, since you want to assess/eval my sequence, therefore better to start with your blade and perhaps can side-to-side compare with your baseline ht-ed blade.
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Email sent.
 
Does Magnacut 64rc with 12dps edge geometry strong enough to support chopping 2x4 and still slice phonebook paper afterward?

Result: Barely passed or almost failed :)

7:42 video

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ice-pic said:
No fractures is encouraging to me,especially at .006",that could be called 6mil foil:)
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Good or not too good is sure depend on one's interpretation & perspective/objective on test result. Per 2 requests on YT, I compiled results for this 2x4 chopping test
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