Heat Treatment - Crystal Weaving Foundation

[Park Swan]

Nate, your posts are consistently helpful and a breath of fresh air. Looking forward to seeing the testing which will undoubtedly be clear and informative. :thumbup:

 

[Ken H>]

.....snip....
It's impossible to take a human element from these tests, so I acknowledge they're not perfect. But I do two side by side and repeatably is generally good, so I take the information I see from this as having value..... snip....

Nathan, I think everyone here views your tests as very honest in approach and testing, that you will give as fair and impartial test results as it's humanly possible to give.

Myself as well as most others on site are looking forward to Luong's process details so we can try it, and to the results of your testing. Your tests have given a lots of credibility to Luong's process with your testing of his blade shipped to you. You confirmed a 65+Rc reading, and confirmed it would chop without damage. Really got my interest!

Ken H>

 

[samuraistuart]

Luong, may I open my mouth and really show my ignorance? You say, "un-tempered", but I've been reading about "aging" after the quench/cryo. This procedure indicates a low temperature soak, maybe not technically tempering? in the area of 250f (give or take?) for 24-48 hours (or more). But if these steels are being used "as-quenched", then please kindly disregard.

While I also would like to see a side by side comparison of CWF HT vs conventional HT, or even CWF HT vs NC HT, (Nathan's), I do think you're moving in a positive direction. Looking forward to a sort of "mission statement" of exactly what you're trying to achieve along with the technical data. We can learn a lot from those.

 

[newdebate]

CWF is pathetically/embarrassingly simple compare to this - http://www.cs.virginia.edu/~robins/A_Geometric_Theory_of_Everything.pdf

This link opens a door.

 

[BluntCut MetalWorks]

Thanks. :thumbup: I always happy to interact with thinkers - so much more fun to discuss ideas & concepts.

Sort of repeat my replied to Devin above... To me:

Aging akin to puss from infection/dislocation. Certain can squeeze it but won't translate into healing.

edit to add (then go offline): Twindog had done a good job with this review - http://www.bladeforums.com/forums/showthread.php/1406383-High-hardness-choppers

Luong, may I open my mouth and really show my ignorance? You say, "un-tempered", but I've been reading about "aging" after the quench/cryo. This procedure indicates a low temperature soak, maybe not technically tempering? in the area of 250f (give or take?) for 24-48 hours (or more). But if these steels are being used "as-quenched", then please kindly disregard.

While I also would like to see a side by side comparison of CWF HT vs conventional HT, or even CWF HT vs NC HT, (Nathan's), I do think you're moving in a positive direction. Looking forward to a sort of "mission statement" of exactly what you're trying to achieve along with the technical data. We can learn a lot from those.

There are many problems from here to there - which maybe solvable and have immediate benefits to all rather than hot puff of theoretical.

This link opens a door.

 

[Nathan the Machinist]

This is a quick and dirty evaluation of a test knife sent to me by Luong. I don’t have the time to do an extremely through comparison, or make the needed full hard control sample, but I can look at a few things here with some accuracy and tighter controls.

The test knife sent to me is 16 ¾”, has an 11 1/8” blade, is .176” at the ricasso and weighs 16.0 ounces. The most remarkable thing about this knife is the hardness, which measures at HRC 65.5.

I ran it though some cuts and used other control knives for comparative reference. Every knife in this test was sharpened at 18 degrees per side on a fresh ceramic belt, at low speed and under flood coolant to prevent issues with a burnt edge being an unknown variable.

These are the test knives:

#1: Luong's Test knife: .037 BTE, HRC 65.5
#2: D3V Field Knife, .030 BTE, (thicker than standard) HRC 61.5
#3: D3V Chopper, .046 BTE (much thicker than standard), HRC 60.5
#4: Industry Standard HT knife, .041 BTE, HRC 60.0



1: The first cut is whittling, carving and light chopping on a piece of seasoned pressure treated pine board. These are sliding shaving cuts with the blade held almost parallel to the work piece. A person might do something like this sharpening a tent stake. Knives in a good steel with a good heat treat will frequently show no sign of damage from this at all.

Results:
#1, One extremely small chip that can be seen with bright light and felt with fingernail
#2, no sign of use
#3, no sign of use
#4, Industry standard HT shows a shiny glittery edge along the length where it was being used.



2: carving whittling cuts in Osage Orange. This involves carving down into and deepening a groove in the wood and torquing it back out. It makes a horrible gritty sound and puts a lot of lateral load on a fine edge.

#1, Very slightly shiny glittery edge, almost no sign.
#2, One extremely small chip that can be seen with bright light and felt with fingernail
#3, One extremely small chip that can be seen with bright light and felt with fingernail
#4, Minor shiny glittery edge that can be seen with bright light and felt with fingernail



3: Chopping into Osage orange. Due to the weight and size difference of these pieces I’ll hold the knife stationary against my bench and swing the wood into the edge. This tests edge stability in impact.

#1, One extremely small chip that can be seen with bright light. Can not be felt with fingernail
#2, small edge roll visible without bright light.
#3, small edge roll visible without bright light.
#4, Moderate edge roll, visible at arms length.



4: carving slivers off a steel nail.

#1, small glittery shiny edge, requires bright light to see
#2, small edge roll, requires bright light to see
#3, moderate edge roll, visible without bright light
#4, significant edge damage visible at an arms length



5: Chopping 16 penny nails. .150" work hardened wire, cut against an aluminum anvil using a 4 pound hammer. All of the knives took significant damage that is visible at an arms length. I ran this test yesterday at 20 DPS and there was much less damage. This shows the significance of a couple degrees in a test like this. Many testers are not controlling this geometric variable close enough to form valid observations.

The least damage was #1 (Luong's) followed closely by #3. #2 has more damage followed by #4 which has damage that goes above the edge bevel.

The final thing I did was chop a 2X4 in half twice without incident. These are hard, well seasoned boards and I hit pretty hard, and my control with this chopper wasn’t great, but there was very little sign of edge roll or micro chipping with no dents to the primary grind.

In conclusion: I don't know what a typical full hard blade would have done in these tests, but common sense tells me it probably wouldn't be great because untempered steel is usually too brittle to hold an edge well in rough use. I don’t know what the application will be for such a high hardness knife, and my testing of this knife was limited and didn’t include long term durability testing. But it certainly seems to me that Luong may be onto something here and his work may have a lot of potential in cutlery heat treat. So I can validate some of the claims made, and it is my opinion that this warrants a closer look.

 

[Ken H>]

Nathan, thank you so much for taking the time for such a detailed test. While it might not be as detailed as your normal tests, I do think it shows there is a LOTS of potential for Luong's HT method - and importantly shows Luong's HT is something new. As I said before, I'm really looking forward to the details of this process for kitchen knives.

Just how will the normal person sharpen a 65 Rc chef's knife? Will it require professional sharpening? Will a standard butcher's steel maintain the edge?

Nathan, Thanks again for your impartial test.

Luong - we're all REALLY looking forward to details for HT'ing AEB-L steel in Dry Ice.

Ken H>

 

[marcinek]

I would like to do that, but it's not in the cards at the moment.

My standard protocol ....

It's impossible to take a human element from these tests, so I acknowledge they're not perfect. But I do two side by side and repeatably is generally good, so I take the information I see from this as having value.

....

I don't expect the outcome of this to be a definitive outcome. But, if it compares well to other known good samples, and untempered 3V would generally not be expected to do so, that would tell me his process warrants a closer look.

Great! Excellent! I understand that definitive results would require a great deal of expense, technology, and time.

But what you are doing sounds systematic (as usual) and would allow one to say, at least, that "Observations show evidence that heat treatment X for steel Y in geometry Z provides a higher optimal hardness."

It'll be nice to hear results from someone who does not think the scientific method deserves ridicule or is "semantics."

If there is evidence of this phenomena, it would also be nice to hear a metallurgist or materials scientist explain the materials science behind it....but one step at a time!

Thanks for doing this and explaining your method, Nathan! :thumbup::thumbup:

 

[FortyTwoBlades]

Will a standard butcher's steel maintain the edge?

Nope. It'd be way too hard for that. You'd have to use something like a ceramic or diamond "steel" honing rod instead.

 

[dogrunner]

Thanks for the report Nathan, and thanks to Luong for his efforts and willingness to be open about all of this.
To Marcinek and others - I appreciate your philosophical views as a research scientist myself (PhD Biology and I teach graduate level research design, scientific inference and data analysis). I think it is certainly true that the scientific approach is not a semantic quibble, but there is also a place for exploration and that is what Luong is doing. The formal experimentation and nailing down of explanations will follow if the standard HT paradigm can't hack it (pun intended ). Others have already made similar arguments - so let's see where this goes! I'm excited by what Nathan has already accomplished and put into production, and intrigued by what Luong has seen already.

 

[Revolverrodger]

Thank you Nathan fir these unbiaised tests
This new HT is indeed very interesting

 

[Revolverrodger]

A question for bluntcut:
Since your new HT adds alot to edge stability and toughness will there still be a toughness advantage to carbon steels or mid chromium steels vs stainless steels ?
Will this change the applications of these steels ?
I for one would love a duper tough stainless steel chopper

 

[chiral.grolim]

...In conclusion: I don't know what a typical full hard blade would have done in these tests, but common sense tells me it probably wouldn't be great because untempered steel is usually too brittle to hold an edge well in rough use...

THAT right there is your "control" By the way, any pics of the test-blade edges? Particularly after the nail cutting?

One of my favorite bluntcut tests is the 66+ Rc blade used immediately after dipping in LN2, a circumstance in which again you'd expect VERY brittle behavior and low impact resistance, but his test suggests otherwise.

[video=youtube;5-mVEp7BiLo]https://www.youtube.com/watch?v=5-mVEp7BiLo[/video]

He has a thread on it: http://www.bladeforums.com/forums/s...tests-and-light-chop-at-cryogenic-temperature

It seems to me the bluntcut actually has a better take on scientific method than a few of those posting here. He uses a similar protocol testing his own blades, moving from softer to harder mediums, and more direct/in-line controlled cutting to ones inducing more lateral stress. No fault has been found in his knowledge of the forces involved in cutting. No fault has been found in his knowledge of metallurgy as he has thus far presented it here and elsewhere. It is from this knowledge that he has developed (through experimentation) the HT protocol used to achieve these results. He tests and re-tests his samples. So here is what is being criticized:

1) "Luong, your theories about the changes to the matrix are fascinating but remain unproven until someone puts the resources into the technology required to ascertain what is really going on." This is what he has stated a desire for, and the reason he is considering going public, so someone else who has the money and time can make it happen, though he may then lose IP rights.
2) "Luong, someone else needs to test those blades." http://www.bladeforums.com/forums/showthread.php/1406383-High-hardness-choppers - actually, a number of others on BF have tested his blades. He has been asking for sincere testers for quite some time, and again a public disclosure of the method would increase that though it means he may lose IP rights.
3) "Luong, I don't understand that your first post in this thread is showing close-up images of experimental results that fly in the face of accepted HT practices! I don't understand that these different steels presented are BOTH commonly thought inacpable of reaching those RC values AND incapable of enduring that type of stress at that geometry with such little damage especially at such high hardness. Indeed, i don't actually understand what different rockwell values correspond to, or to what extent and also what limit edge-geometry impacts durability. You aren't doing "science" (as i think i understand it)." This is a criticism that missed the point of the very first post and seems to argue semantics of "what is science" without understanding the process itself, i.e. discovery. If you can't hack it as it has been presented, please wait for the "scientific american" news article explaining it. :thumbup:

In my own professional field (organ transplant research) the process toward discovery is actually quite analogous to what Luong is doing here, and often much less controlled.

IF Luong's efforts can be proven via adoption by other knifemakers and indeed other Steel HT companies, it will certainly revolutionize the industry. Consider that the primary mode of wear on our knives is not abrasion but apex deformation or chipping, using harder blades that do not suffer substantial loss in toughness is a great leap forward IF the cost is not substantially increased, and ESPECIALLY IF it can be done in stainless steel. I have typed this elsewhere but will do so again - imagine a WC-Co carbide blade with the toughness of L6 and able to be sharpened with standard abrasives. :thumbup:

Then again, perhaps it will make no difference whatsoever on a grand scale. We are so awash in steel formulations, most of which have nothing to do with knives but many work well enough, and the most popular steels are still 1095 and 420HC at 56-58 RC or lower or a variation thereof, blades that will be readily damaged by the tests detailed by Nathan and Luong and others, but the damage they sustain in normal use can be easily repaired, often with only a "butcher's steel" as previously mentioned.
i don't recall much impact from Gerber using M2 steel for a while...

 

[chiral.grolim]

5: Chopping 16 penny nails. .150" work hardened wire, cut against an aluminum anvil using a 4 pound hammer. All of the knives took significant damage that is visible at an arms length. I ran this test yesterday at 20 DPS and there was much less damage. This shows the significance of a couple degrees in a test like this. Many testers are not controlling this geometric variable close enough to form valid observations.

Nathan and Luong both already have a firm grasp of this, but for those wondering, here is a quick chart detailing the difference in edge strength when you sharpen at different angles:

 

[BluntCut MetalWorks]

Nathan,

Thanks very much for taking time & resource (yeah like fixed up my chopper grind & bevel to meet your higher test specs) & this review :thumbup: Your confident; courage & professionalism are assets to BF. And please stop being too generous OK ->? Offer to help me to build a better chopper... no thanks, I don't know how to eat 3V chopper pie

Best,
==Luong

This is a quick and dirty evaluation of a test knife sent to me by Luong. I don’t have the time to do an extremely through comparison, or make the needed full hard control sample, but I can look at a few things here with some accuracy and tighter controls.

...
In conclusion: I don't know what a typical full hard blade would have done in these tests, but common sense tells me it probably wouldn't be great because untempered steel is usually too brittle to hold an edge well in rough use. I don’t know what the application will be for such a high hardness knife, and my testing of this knife was limited and didn’t include long term durability testing. But it certainly seems to me that Luong may be onto something here and his work may have a lot of potential in cutlery heat treat. So I can validate some of the claims made, and it is my opinion that this warrants a closer look.

 

[BluntCut MetalWorks]

Abrading depth will be a little shallower as matrix is high and could be bad of abrasive binding strength is very low (e.g. very soft stone). For blades w/o load of VC, I use my old cheapo no-name $10(600/1K) & $30(2K/5K) waterstones on amazing-bigriver store.

Butcher's steels (smooth & groove) are too soft, so the blade will burnish/cut them. Depend on lateral force involves with steeling - this process could/probably degrade the blade edge.

I think DI will works fine but LN2 is probably optimal.

...
Just how will the normal person sharpen a 65 Rc chef's knife? Will it require professional sharpening? Will a standard butcher's steel maintain the edge?
...
Luong - we're all REALLY looking forward to details for HT'ing AEB-L steel in Dry Ice.
Ken H>

 

[BluntCut MetalWorks]

Thanks.

Sir/dude - thanks for stepped on my fingers on the ledge of the metallurgy rabbit hole with your ridiculous requirements... A tough blade works well in sub zero temperature - aha sure Hopefully -320F/-195C temperature isn't too warm for you

Thanks for the report Nathan, and thanks to Luong for his efforts and willingness to be open about all of this.
To Marcinek and others - I appreciate your philosophical views as a research scientist myself (PhD Biology and I teach graduate level research design, scientific inference and data analysis). I think it is certainly true that the scientific approach is not a semantic quibble, but there is also a place for exploration and that is what Luong is doing. The formal experimentation and nailing down of explanations will follow if the standard HT paradigm can't hack it (pun intended ). Others have already made similar arguments - so let's see where this goes! I'm excited by what Nathan has already accomplished and put into production, and intrigued by what Luong has seen already.

 

[Bill1170]

Nathan and Luong both already have a firm grasp of this, but for those wondering, here is a quick chart detailing the difference in edge strength when you sharpen at different angles:

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.

 

[BluntCut MetalWorks]

Yes. I've good guess - quantitative wise - on pro/con.

Yes. You don't need a capable 200mph car to commute when salt will rust it out in a few years. Obviously a 150MPH capable + corrosion resistant is way better

A question for bluntcut:
Since your new HT adds alot to edge stability and toughness will there still be a toughness advantage to carbon steels or mid chromium steels vs stainless steels ?
Will this change the applications of these steels ?
I for one would love a duper tough stainless steel chopper

 

[BluntCut MetalWorks]

___:thumbup:
:thumbup:Chiral:thumbup:
___:thumbup:

PM sent.

...
One of my favorite bluntcut tests is the 66+ Rc blade used immediately after dipping in LN2, a circumstance in which again you'd expect VERY brittle behavior and low impact resistance, but his test suggests otherwise.
...