Heat Treatment - Crystal Weaving Foundation

What are min and max working resolution/granularity of crystal cell/thread size of CWF and also turning radius? This hairy question came up in private disclosure.

Um not sure... won't cut it. So, this weekend (hopefully time permits), I will weave 5-10 7" blades to gather some data to cover my b**t and give public a decent working range rather mass try-out.
 
Bill1170 said:
Thanks for posting that graph. It'd be interesting to see another graph showing edge angle graphed against force needed to cut a standard sample.
Click to expand...

EDIT: I re-normalized the strength chart to 25-dps (50-inclusive) and normalized the cutting-ability chart to 2.5-dps (5-inclusive) to put them on the same scale, then combined the charts. These are normalizations of idealized values, reality is more complex but will generally behave accordingly.

"Cutting Efficiency" is simply mechanical advantage - a knife edge is a simple wedge, it requires X amount of force to penetrate to depth Y when the blade is ground at angle Z since the primary reason it takes that much force is because of the increasing thickness of the wedge up to that depth. On a very wide blade making very deep cuts, frictional force could come into play but I've ignored it in this chart for a variety of reasons. I normalized to 2.5-dps because below that the cutting efficiency increases at a rate that leaves all other values in the dust, but 2.5-dps as an actual edge-bevel angle is already below what is practically achievable as it is so weak, seems like a good lower-bound.

"Edge Strength" is simply rigidity against lateral stress, which relates cubically to edge thickness. 25-dps was again chosen simply to help illustrate the relative values for angles commonly encountered on our knives.


Normalized%2BEdge%2BAngle%2BCharts.png



EDIT to add: this post and chart is relatively off-topic as it ignores HRC values. It is meant to compare two aspects of performance in blades with similar hardness or even just a single blade at different geometries. What i hope is very clear is the difference in how each graph behaves over a given range of values. For example, taking a blade from 20-dps down to 15-dps enhances cutting efficiency by ~36% but drops edge-strength by ~60% - that is a definite tradeoff, but it is one that can be mitigated by means of a micro-bevel at a heavier angle for the first few microns followed by a thinner angle beyond the "danger zone" where damage is unlikely to reach. But that is a discussion taken up in other threads, so I'll stop de-railing this one :p
 
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Grain size & boundary play a huge role in strength, especially when movement involves.
https://en.wikipedia.org/wiki/Grain_boundary_strengthening

Definition of toughness https://en.wikipedia.org/wiki/Toughness can have fairly wide/vague interpretation. Does a chopper made out of iron tough? or is it just plain ductile?

https://en.wikipedia.org/wiki/Young's_modulus, flexing/bending a same length fillet knife vs a chopper made from same steel+ht, flex degrees is drastically different between the 2.

Smaller grain will have wider elastic range. Just imagine each grain is made out of 1 solid diamond. If the blade is mono(or no) grain, it sure won't bend much... keep reduce grain/diamond size ... first link.

My W2 R&D has a lot to do with grain refinement. While my D2 R&R would be grain & carbide refinement. Um hint ... I don't like PM steels mondo (2-5um) carbides.

Revolverrodger said:
Bluntcut how about lateral strength test (blade flexing)
It could give an idea how tough the chopper will be
Click to expand...
 
chiral.grolim said:
EDIT: I re-normalized the strength chart to 25-dps (50-inclusive) and normalized the cutting-ability chart to 2.5-dps (5-inclusive) to put them on the same scale, then combined the charts. These are normalizations of idealized values, reality is more complex but will generally behave accordingly.

"Cutting Efficiency" is simply mechanical advantage - a knife edge is a simple wedge, it requires X amount of force to penetrate to depth Y when the blade is ground at angle Z since the primary reason it takes that much force is because of the increasing thickness of the wedge up to that depth. On a very wide blade making very deep cuts, frictional force could come into play but I've ignored it in this chart for a variety of reasons. I normalized to 2.5-dps because below that the cutting efficiency increases at a rate that leaves all other values in the dust, but 2.5-dps as an actual edge-bevel angle is already below what is practically achievable as it is so weak, seems like a good lower-bound.

"Edge Strength" is simply rigidity against lateral stress, which relates cubically to edge thickness. 25-dps was again chosen simply to help illustrate the relative values for angles commonly encountered on our knives.


Normalized%2BEdge%2BAngle%2BCharts.png



EDIT to add: this post and chart is relatively off-topic as it ignores HRC values. It is meant to compare two aspects of performance in blades with similar hardness or even just a single blade at different geometries. What i hope is very clear is the difference in how each graph behaves over a given range of values. For example, taking a blade from 20-dps down to 15-dps enhances cutting efficiency by ~36% but drops edge-strength by ~60% - that is a definite tradeoff, but it is one that can be mitigated by means of a micro-bevel at a heavier angle for the first few microns followed by a thinner angle beyond the "danger zone" where damage is unlikely to reach. But that is a discussion taken up in other threads, so I'll stop de-railing this one :p
Click to expand...
Thank you for those charts.
The title on the middle graph should read, "...normalized to 25dps," not 45dps, right?
 
Sneaked some ht time to test out a mid-resolution/granularity weave. Didn't pulled off a successful multitasking work+ht at the same time. The 0.12" thick M2 chopper came out look like a left parenthesis "(" because it falled and leaned on 1 fixture post in ht oven at 2200F. Almost pull off a straighten job but greed yielded 2 pieces. Oh well, will test nothing but blade chopper :)

Chopped: soft-to-superhard-wood, thin metal tube, thick aluminum tube, red brick, 2.5" thick aggregate concrete, thick wire and ... either a big chip or break, so decided to chop into a 5/16" thick steel bar. Chipped up to 0.039" thick. Made a bunch of hard side slaps, no cracks/stress-risers. I am happy with this mid-resolution CWF.

7wAt78l.jpg


https://www.alphaknifesupply.com/zdata-bladesteelC-M2.htm
 
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Luong, what you're doing is very interesting, and it seems to have interesting results, but I am very confused by your explanations. You also have a few misconceptions about toughness and flexibility, but they're not really relevant.

I am a materials scientist, so I have no problems with your terminology, but when you simply throw around technical terms like potential, activation, and bravais lattices you aren't really explaining anything. That said, I'm not particularly interested in your process right now, I'm very interested in what you think you have achieved. What is it exactly that you think makes your steel strong and tough at the same time? Also what is your final microstructure (i.e. is it pure martensite with carbides, ferrite/martensite/cementite or something else?), and what exactly do you mean by "crystal weaving"?

Forgive me for being cynical. It's easy for others to simply accept what you say if they don't understand metallurgy, but I do understand metallurgy, even if I'm not an expert, and nothing you said has made sense so far.
 
Are you power grinding at all after heat treat? If so, do you use a wet grinding setup?

I have to admit that your posts never make sense to me. If you used plain language rather than technical terminology, it would probably make more sense to me (and I'm assuming most others who are reading this).
 
Nathan has similar concern about burned-edge prior to test my 3V chopper. His result helped lower the chance of equipment error issue. I grind post-ht (wouldn't be fun at all to grind primary bevel for hardened high alloy blades) with 2hp vfd 2x72 grinder.

At some point results maybe more effective by SHOW instead of TALK, right :) I am working toward that...

S.Alexander said:
Are you power grinding at all after heat treat? If so, do you use a wet grinding setup?

I have to admit that your posts never make sense to me. If you used plain language rather than technical terminology, it would probably make more sense to me (and I'm assuming most others who are reading this).
Click to expand...
 
I guess my thoughts are (without knowing your exact process), if you aren't tempering your blades, then maybe when you are grinding them post heat treat you are in fact tempering the edge slightly.

I definitely don't know this for certain, Im just throwing the idea out there for discussion.
 
For the sake of discussion, if you don't mind to pretend that what shown in post #1 are factual - evidences(blessed by Sir Harry Bhadeshia - my top respected metallurgist btw) of improved blades/hardened-steels. Or creatively, I can travel to the future - a few weeks from now - to confirmed that CWF ht indeed produce higher performance blades than conventional ht.

From ^, an obvious conclusion: CWF ht produces higher performance Martensite matrix than conventional ht because improvement is across spectrum of steel from no alloy simple to high alloy complex steels. So, I can sum up whether my 'weave' or other processes taken place as:
1. Got good result with wrong reasons(no weave crapola) - well then, better lucky than good :)
2. Got good result with weaved mart matrix - well well, lucky blind squirrel found nut sometime :D

From post#86 - conceptual model is simply a Combinatorial Optimization Graph representing 1 grain of aust matrix, which only involve Aust & Mart crystal structure. Hence, NO: ferrite; carbide; free elements and even grain boundary.

Optimization Goal:
1. optimize for highest number of edges from 1N to 2N (can't get to 2N because of volume skin/outer surface). Strength & toughness components.
2. least increase in volume radius. This is spatial/dimension component, which affect inter-grain.

Post #61 - Ideal structure in my mind = weaved lattice. Thus orientation/vector(i.e. has direction) must change but most likely be orthogonal.

Conventional ht - Martensite orientation in a grain is predominantly matched austensite prior to transformation.

My assertion/claim with CWF ht:
1. martensite orientation are 360*, where directional change depend on resolution/granularity of mart cell size.
2. because of 1. RA can be reduce to drastically lower than any conventional ht (at untempered state). Will explain conceptual reason for this when CWF 'how' is disclose.

*** OK, now back to reality present ***
CWF will get publish/disclose - maybe it's my delusional but I think then benefit would be much larger than here. Without this very reason, I would laugh all the way to the bank:p

SPNKr said:
Luong, what you're doing is very interesting, and it seems to have interesting results, but I am very confused by your explanations. You also have a few misconceptions about toughness and flexibility, but they're not really relevant.

I am a materials scientist, so I have no problems with your terminology, but when you simply throw around technical terms like potential, activation, and bravais lattices you aren't really explaining anything. That said, I'm not particularly interested in your process right now, I'm very interested in what you think you have achieved. What is it exactly that you think makes your steel strong and tough at the same time? Also what is your final microstructure (i.e. is it pure martensite with carbides, ferrite/martensite/cementite or something else?), and what exactly do you mean by "crystal weaving"?

Forgive me for being cynical. It's easy for others to simply accept what you say if they don't understand metallurgy, but I do understand metallurgy, even if I'm not an expert, and nothing you said has made sense so far.
Click to expand...
 
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Thanks for thinking of scenario. I think, Nathan & I would easily spot behavior of a softer edge (i.e. roll rather than chip). It could be my 3V chopper edge is only 63rc but in perspective of performance - it doesn't matter, right. I actually, do use my test blades edge to whittle a poor spyderco dragonfly zdp-189 blade spine. Softer steel loose.

S.Alexander said:
I guess my thoughts are (without knowing your exact process), if you aren't tempering your blades, then maybe when you are grinding them post heat treat you are in fact tempering the edge slightly.

I definitely don't know this for certain, Im just throwing the idea out there for discussion.
Click to expand...
 
SPNKr said:
Luong, what you're doing is very interesting, and it seems to have interesting results, but I am very confused by your explanations. You also have a few misconceptions about toughness and flexibility, but they're not really relevant.

I am a materials scientist, ...
Click to expand...

Thank Scagel we got a materials scientist in this thread! It needs one desperately.
 
S.Alexander said:
Are you power grinding at all after heat treat? If so, do you use a wet grinding setup?

I have to admit that your posts never make sense to me. If you used plain language rather than technical terminology, it would probably make more sense to me (and I'm assuming most others who are reading this).
Click to expand...

Sounds like they are not making much sense to SPNKr, the materials scientist, either.
 
Where are we? :thumbup:

1. evidences exist but I don't know how that can be done?
2. evidences exist, I want to know 'how' now or else Luong have been posted nonsense?
3. interesting:rolleyes:, need evidences and 'how' as well?
4. waste of time - I am out of here?
 
5. Interested, confused, curious but would like evidence and "how" to show this can be done by anyone, but seems to have been "overlooked" until now.
 
Some where above, I posted... I want to conduct 1 more round of test to come up with reasonable answer on weave resolution/granularity (clearer term would be too much of a hint :)). Better me spend 1 person time than a lot of people try to figure out the same thing.

When 'how' is out - many will slap forehead "why didn't I try/think that".

NJBillK said:
5. Interested, confused, curious but would like evidence and "how" to show this can be done by anyone, but seems to have been "overlooked" until now.
Click to expand...
 
Got to remember some things may be lost in translation as well. But in the end if the results end up being superior and can easily be repeated than I think
whatever the method is, Luong has come up with something new which in itself if pretty impressive when it comes to heat treating.
 
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