CPM3V vs CPM4V

Ankerson said:
Low temp tempering..... Under the recommended 800F to 1000F.....

Tempering at 400F to 500F.

One might gain toughness, but it kills edge retention.
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I'm not sure if you have a clue on what you are talking about... The purpose of low temp tempering on Cold work CrMoV alloy steel is to avoid secondary hardening for higher percentage carbon martensite which mean stronger matrix thus higher edge stability and toughness... at the plus of better corrosion resistance due to free Cr remained. Note that the low temp tempering recipe must be combined with cryo follow the quench to convert RA because low temp tempering is not hot enough to dissolve it.

This theory is publish to the knife making world by Roman Landes... and now it is well known through the heat treat industrial...

Dan Keffeler, Peters Heat treat and many more custom knife maker also follow this procedure. There are many proof that this method is better for cutlery application.

There are reason why Elmax, M390, S30V and many PM alloy steel are all tempering at 400F range.
 
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Also there are nothing to do with the word "high end" just by choosing to do the tempering at 1000F range...
 
shqxk said:
I'm not sure if you have a clue on what you are talking about... The purpose of low temp tempering on Cold work CrMoV alloy steel is for avoid secondary hardening for higher percentage crbon martensite which mean stronger matrix thus higher edge stability and toughness... at the plus of better corrosion resistance due to free Cr remained.

This theory is publish to the knife making world by Roman Landes... and now it is well known through the heat treat industrial...

Dan Keffeler, Peters Heat treat and many more custom knife maker also follow this procedure. There are many proof that this method is better for cutlery application.

Elmax, M390, S30V and many PM alloy steel are tempering at 400F range.
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If the specs call for it... ;)

If not then it's not within specs and it hurts performance.
 
Ankerson said:
If the specs call for it... ;)

If not then it's not within specs and it hurts performance.
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What??? cryogenic is not within specs of 3V and many others steel... so why there are numbers of knife makers who bothers with it? Do you know proper L2N dewar is not cheap... I guess may be because most of them don't know shit, right? :rolleyes:
 
shqxk said:
What??? cryogenic is not within specs of 3V and many others steel... so why there are numbers of knife makers who bothers with it? Do you know proper L2N dewar is not cheap... I guess may be because most of them don't know shit, right? :rolleyes:
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I talked the Steel guys at Blade last year and more than a few times on the phone about this subject.

And I did some of the testing myself.....

There is a HUGE difference.....
 
Ankerson said:
I talked the Steel guys at Blade last year and more than a few times on the phone about this subject.

And I did some of the testing myself.....

There is a HUGE difference.....
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Who is your Steels guy at blade and who you talked on the phone?

I talked to Dan Keffeler and PhD metallurgist about this subject for years because I plan to heat treat my friend blade... I'm sure there are also a lot of knife makers here that do the low temp with 3V. Would you mind to educate us about this because you word about the test are really interesting...??
 
shqxk said:
Who is your Steels guy at blade and who you talked on the phone?

I talked to Dan Keffeler and PhD metallurgist about this subject for years because I plan to heat treat my friend blade... I'm sure there are also a lot of knife makers here that do the low temp with 3V. Would you mind to educate us about this because you word about the test are really interesting...??
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The guys who make the steel. ;)

Call or email Crucible and ask them. ;)

Dan doesn't do his own heat treating by the way, I know Dan.
 
Ankerson said:
The guys who make the steel. ;)

Call or email Crucible and ask them. ;)

Dan doesn't do his own heat treating by the way, I know Dan.
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Dan Keffeler is one of the very first makers that made katana out of CPM-3V and chopped down trees with it. He sent all of his work to Peters and if I'm not mistaken he is the one who sent his own 3V heat treat protocol to Peters and now it is a commercial standard for them.

I'm not sure about the guy who make it part because Crucible is such a big company... even the guy who invented the steel, if he still alive he would have to follow the modern metallurgy because science nowaday are much more advance ...
 
I know what some are doing it.... ;)

But the problem is that to gain what they are gaining in toughness they lose in edge retention.

I did direct comparisons myself along with some others.
 
shqxk said:
Dan Keffeler is one of the very first makers that made katana out of CPM-3V and chopped down trees with it. He sent all of his work to Peters and if I'm not mistaken he is the one who sent his own 3V heat treat protocol to Peters and now it is a commercial standard for them.

I'm not sure about the guy who make it part because Crucible is such a big company... even the guy who invented the steel, if he still alive he would have to follow the modern metallurgy because science nowaday are much more advance ...
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I know Dan personally. ;)

I won't go into it other than to say you might want to talk to him again.
 
I know Dan pretty well. And Peter's too. :thumbup:

Ankerson said:
If the specs call for it... ;)

If not then it's not within specs and it hurts performance.
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^ This is not accurate.

The protocol developed by the makers of the steel was optimized for tool and die, not cutlery. While avoiding the use of the secondary hardening hump is not without some potential pitfalls, that is where there is the best potential for cutlery.

These pictures illustrate the difference between the industry standard heat treat with SHH and one optimized for cutlery:

tweak_10CA.jpg~original


tweak_10CA2.jpg~original


This is a video that illustrates one aspect of some of the testing: https://www.youtube.com/watch?v=6imZ4Vo8iwA

This is a demo video that shows a real application: https://www.youtube.com/watch?v=yC2PLk_04vE

3V, when used in cutlery, should be tempered between 400 and 500 for best performance. There is more to it than that, but for sure, the SHH leaves a lot on the table.
 
Ankerson said:
I know what some are doing it.... ;)

But the problem is that to gain what they are gaining in toughness they lose in edge retention.
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Do you know that toughness is also a part of edge retention? That the reason why ceramic blade wouldn't hold an edge for long... You sound confused about your understanding to be honest.

The main point for low range tempering is not for toughness but for stronger martensite matrix and lesser Cr carbide which are precipitate at 1000F tempering which have chance to occur at grain boundaries and weaken the blade...
 
Never mind...

You guys just keep doing what you are doing. ROFL
 
Ankerson said:
You people are funny. :rolleyes:

Not worth my effort.
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I have no idea how ridiculous people can be... You came in like you know everything, criticize on thing that you don't actually know... and at last it shown up that you have no clue.

But seems like your ego is strong so I wouldn't bother.
 
There are 3 main advantage reasons for using SHH

1. Lack of LN2 for cryo quench/soak.

2. Usage applications+styles that leverage larger(due to diffusive coarsening) SHH precipitated carbides (mostly Cr7C3) along with higher carbide volume. e.g. draw cutting abrasive materials.

3. A decent way to salvage from overheated aust. In this event RA TKO LN2, only 1000F-1050F will create enough space for RA -> mart conversion. Sour lemonade is better than s/crap metal.

So, Ankerson's takes are applicable/correct, especially in the context of rope-cutting (cut in air, while impact to backing is a minus for SHH).

My WAG over all performance view on SHH vs LTT(low temper temp) is 25/75. For sub 20dps edge tools, all others benefits posted by Nathan & shqxk out weight SHH by 3/1.
 
I may regret this post later, but the way I understand things, the two varying heat treatments have their place. For example, if the knife is going to see impact use, the modified HT Nathan discusses is going to be better. If the knife is going to be doing mostly slicing cuts on abrasive material, then I would expect the higher tempering temps to be better in that application. Just a guess. Tomatoes....incoming!
 
Too late but I am willing to change the quoted-text for a substantial price :p

Slice constists of lateral% + penetration% depend on material stiffness. For soft abrasive material (says soft muddy sand), cutting is mostly push/penetration, so SHH lower strength matrix won't do as well as LTT. Otoh, For ropes; sandy woods; etc... slicing, high cv% and larger carbides of SHH will certainly better because carbides shield matrix from low angle abrasion.

samuraistuart said:
I may regret this post later, but the way I understand things, the two varying heat treatments have their place. For example, if the knife is going to see impact use, the modified HT Nathan discusses is going to be better. If the knife is going to be doing mostly slicing cuts on abrasive material, then I would expect the higher tempering temps to be better in that application. Just a guess. Tomatoes....incoming!
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