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This is true, but HSS and D2 are and discussed in the paper.
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Super duper CPM-s3v heat treatment recipe?
- Thread starter JG Custom Metal Works
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AV, do you do your own heat treating? If so, what are some of your most used alloys? Have you done any testing comparing blades with and without cold treatments?
Impact toughness is what we are talking about here and not durability.
I believe CT is necessary for optimum heat treatment in most cases for knives.
Hoss
Impact toughness is what we are talking about here and not durability.
I believe CT is necessary for optimum heat treatment in most cases for knives.
Hoss
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No actually you stated I made a conclusion when I posted the paper. I am reading the research and not making a definitive statement at all.
The finding varies as I stated, when reviewing the entire paper it talks about metals that improved toughness, such as HSS and D2, and others that did not.
That is why the "Findings vary".
Larrin
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I think if you look at my post again you will see that I asked you a question.
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Devin do you have a problem with the paper when it discusses D2 and HSS improved in toughness?
As for your question I go to TruGrit, which is local and knifemaker Jeff Mutz, who is a personal friend, does the heat treating. I use AEB-L, CPM 3V, ATS 34, 10V, A2, D2, Zfinit and M2 and have all of them cryoed in LN. As do you, I find LN cryo treament to improve performance in certain steels.
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You were "Strawmanning" me
AV, the paper compares the toughness differences using different cryo treatments of D2, not toughness difference between cryo treated D2 and non treated D2.
Austenite is tougher than martensite, by eliminating austenite, there is a natural drop in toughness.
Cryo/cold treatments are used to increase wear resistance and to control distortion in tool steels.
Hoss
Austenite is tougher than martensite, by eliminating austenite, there is a natural drop in toughness.
Cryo/cold treatments are used to increase wear resistance and to control distortion in tool steels.
Hoss
Impact toughness is measured using charpy testing which Ed Severson (former cucible metalurgist) called "wackability" of steel.
Charpy coupons are clamped down and a weight swings down and strikes the steel breaking it and measures how far it swings past the coupon. Certain steels can move past the machines ability to measure because the do not break.
Hoss
Charpy coupons are clamped down and a weight swings down and strikes the steel breaking it and measures how far it swings past the coupon. Certain steels can move past the machines ability to measure because the do not break.
Hoss
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To throw more into the mix from
https://www.researchgate.net/profil...d_hardness/links/544f99580cf2bca5ce92a8db.pdf
"Rhyim et al. [45] and Wierszyłłowski et al. [46] have reported that deep cryogenic treatment improves hardness but reduces impact toughness of AISI D2 steel as compared to conventional heat treatment. Yun et al. [35] have reported that deep cryogenic treatment improves hardness (3–7%) marginally, bending strength (20%) and impact toughness (43%) considerably of AISI M2 steel over conventional heat treatment. A review of literature partnering to the influence of sub-zero treatments in general and deep cryogenic treatment in particular on the mechanical properties of steels reveals that there is little consensus regarding the effect of sub-zero treatments on the mechanical properties of steels apart from the fact that hardness improves marginally. For example, Yun et al. [35] and Prabhakaran et al. [56] have claimed that sub-zero treatments improve impact toughness of steels over conventional heat treatment, but the opposite trend of results have been reported by Zhirafar et al. [30], Zurecki [36], Rhyim et al. [45], Wierszyłłowski et al. [46], Molinari et al. [59] and Harish et al. [66]. While, Zhirafar et al. [30] have shown that deep cryogenic treatment improves fatigue properties of steels than that achieved by conventional heat treatment, the opposite has been reported by Baldissera et al. [31], Bensely et al. [57] and Jung et al. [67]. The above discussion clearly indicates out that the influence of sub-zero treatments on the microstructure and mechanical properties of tool/die steels is far from being understood"
https://www.researchgate.net/profil...d_hardness/links/544f99580cf2bca5ce92a8db.pdf
"Rhyim et al. [45] and Wierszyłłowski et al. [46] have reported that deep cryogenic treatment improves hardness but reduces impact toughness of AISI D2 steel as compared to conventional heat treatment. Yun et al. [35] have reported that deep cryogenic treatment improves hardness (3–7%) marginally, bending strength (20%) and impact toughness (43%) considerably of AISI M2 steel over conventional heat treatment. A review of literature partnering to the influence of sub-zero treatments in general and deep cryogenic treatment in particular on the mechanical properties of steels reveals that there is little consensus regarding the effect of sub-zero treatments on the mechanical properties of steels apart from the fact that hardness improves marginally. For example, Yun et al. [35] and Prabhakaran et al. [56] have claimed that sub-zero treatments improve impact toughness of steels over conventional heat treatment, but the opposite trend of results have been reported by Zhirafar et al. [30], Zurecki [36], Rhyim et al. [45], Wierszyłłowski et al. [46], Molinari et al. [59] and Harish et al. [66]. While, Zhirafar et al. [30] have shown that deep cryogenic treatment improves fatigue properties of steels than that achieved by conventional heat treatment, the opposite has been reported by Baldissera et al. [31], Bensely et al. [57] and Jung et al. [67]. The above discussion clearly indicates out that the influence of sub-zero treatments on the microstructure and mechanical properties of tool/die steels is far from being understood"
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" wackability " ? Never taught me that word in my metallurgy school ! But we did it differently in Brooklyn !
I always found with impact tests they were better used as guidelines rather than absolutes . And there are still things we don't know about cryo [ -300 F ] .
I always found with impact tests they were better used as guidelines rather than absolutes . And there are still things we don't know about cryo [ -300 F ] .
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" far from being understood " That's what I said until you snuck in before me !! It's very obvious to me that there still is a great lack of understanding that
Sub-zero , [ ~ -100 F ,transforms more austenite to martensite , reducing RA , making it harder but less tough.. and Cryogenic cooling which does little to further reduce RA , and little to increase wear resistance .
That wear resistance is due for the most part to the formation of eta carbides !! Two different stories and two different results. Check back to my links , it's there !
Sub-zero , [ ~ -100 F ,transforms more austenite to martensite , reducing RA , making it harder but less tough.. and Cryogenic cooling which does little to further reduce RA , and little to increase wear resistance .
That wear resistance is due for the most part to the formation of eta carbides !! Two different stories and two different results. Check back to my links , it's there !