52100 vs W2

Thanks Don!

My 4th HT (post #10) used 1500F aust temp with short soak time, tried to get higher hardness via higher temperature and mostly kept at-quench RC by low temper temperature (2 long snap tempers).
4th ht:
Normalised (with tool wrap) 1600F 10 minutes soak; hardening 1500F 5 minutes soak; Park50 quenched; cryo; 2x 325F tempered.

​

Don - OK 1450F (3 minutes soak?), shall I perform any normalize / thermal cycle / sub-crit anneal steps too?

My view into wear resistance for Aldo current steels composition: 52100 - 0.94%C & 1.42%Cr (translate to 27 carbide per 1000 atom). W2 - 0.93%C & 0.08%Cr & 0.17%V (translate to 1.5 CrC+3.3VC). Excess Carbon not used by tempered matrix form & precipitate mostly into FeC form. Given everything else optimal, I expect/guess 52100 27 CrC be more wear resistance than W2 1.5 CrC + 3.3VC. That is in theory but perhaps botched-ht is my reality.

Don Hanson III said:
I would question your heat treatment of the W2. I haven't done any scientific tests, but my W2 blades are noticeably better than the 52100 blades I made years ago. In edge holding and toughness at higher Rc numbers... It Kills 1084 & 1095!

I've found 1450 and less soak time to give much better results. 68.5 Rc right out of the quench (Parks50) and 62-63 after two 1 hours temper cycles at 425, or 61-62 at 450.

Not all W2 is the same though. It varies widely...
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I have no way to test my hardness. But I austenitized at 1450 for 15 minutes, quench in p50. That was after the 1650 normalizing, and 1500, 1450, and 1400 grain refinement, and 1250 spherod anneal. I did a snap temper last night at 360F, and it's in again right now at 400f. I did do a file test after quench.....sounded like glass skating off! I know what you mean, Willie, about the discrepancy of Mf. The chart that I saw didn't even go below 0 celcius. It was really about carbon steels, and showed a carbon content of 1% with no alloys having an Mf of around 375F, and if the total alloying was only 1%, the Mf is dropped to about 300F. The more alloying, the lower the Mf. And basically, IIRC with the chart in my mind's eye, you have to get to stainless numbers (alloying totaling over maybe 10%-13% to get below freezing). I'll try to find that again and post it.
 
I don't know hardness for my 4 ht attempts were but file was skidded for all 4 times. I am quite sure that my 1460F aust and super-quenched would harden even low carbon (0.4-0.5%C) into the 60RC range. My puzzlement - where are my carbide? oh come on, Carbon where are you hiding/locked-up or are you there?
 
I triple normalized and clay quenched a W2 blade about a week ago. Just now polishing it out. My tester indicated a hardness of 61/62 on the tang where I left it full hard after 1.5 hours at 400 degrees.

2hhhvyo.jpg
 
bluntcut said:
Thanks Don!

My 4th HT (post #10) used 1500F aust temp with short soak time, tried to get higher hardness via higher temperature and mostly kept at-quench RC by low temper temperature (2 long snap tempers).
4th ht:
Normalised (with tool wrap) 1600F 10 minutes soak; hardening 1500F 5 minutes soak; Park50 quenched; cryo; 2x 325F tempered.

​

Don - OK 1450F (3 minutes soak?), shall I perform any normalize / thermal cycle / sub-crit anneal steps too?

My view into wear resistance for Aldo current steels composition: 52100 - 0.94%C & 1.42%Cr (translate to 27 carbide per 1000 atom). W2 - 0.93%C & 0.08%Cr & 0.17%V (translate to 1.5 CrC+3.3VC). Excess Carbon not used by tempered matrix form & precipitate mostly into FeC form. Given everything else optimal, I expect/guess 52100 27 CrC be more wear resistance than W2 1.5 CrC + 3.3VC. That is in theory but perhaps botched-ht is my reality.
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Yes, normalize, I do, but with no soak time, just bring up to even heat and air cool to black. I don't do a sub-crit anneal, but it can't hurt. 1450 w/3 minutes soak should give better results. I get the highest as quenched Rc (68.5) at 1450-1475. Lower or raise temp and Rc goes down.
 
Bluntcut, looking at the HT cycles you did, it's possible on tests 2,3,4 that the carbon is in the grain boundaries. My second thought is a 325f temper should leave the w2 very hard/brittle. Is the edge possibly microchip ping causing the loss of edge?
 
Don, you have been one of my go to guys with W2 heat treat. I've checked out your posts on more than one occasion in learning W2!!! Thanks for all your help! I was surprised to read that you're getting those high Rc numbers (68.5!!!!!!!! My goodness!!!!!!), especially with a SHORT soak of a few minutes!! That is interesting to me. I guess the reason being, if we've normalized properly, then the carbon is where it needs to be already? I've also read that when spheroidizing, a longer soak is needed to put those carbides back into solution, hence my 15 minute soak time. I would think if the steel has been spheroidized well, it would need that extra time at temp. And I see you're not doing that sub critical anneal....so your short soak times are giving you great results. I didn't know you could get 68.5! Incredible.
 
samuraistuart said:
Don, you have been one of my go to guys with W2 heat treat. I've checked out your posts on more than one occasion in learning W2!!! Thanks for all your help! I was surprised to read that you're getting those high Rc numbers (68.5!!!!!!!! My goodness!!!!!!), especially with a SHORT soak of a few minutes!! That is interesting to me. I guess the reason being, if we've normalized properly, then the carbon is where it needs to be already? I've also read that when spheroidizing, a longer soak is needed to put those carbides back into solution, hence my 15 minute soak time. I would think if the steel has been spheroidized well, it would need that extra time at temp. And I see you're not doing that sub critical anneal....so your short soak times are giving you great results. I didn't know you could get 68.5! Incredible.
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Thanks man! I've never done spheroidizing on W2, just three normalizing cycles. I also use a vertical forge and not a oven, I know that goes against the 'experts' but it sure works for me. Sometimes I think we can over-think this stuff... I got into this W2 for the hamon, but the high performance was a good surprise. I also got W2 (cutoffs) from the same source I got the huge volume of round stock that didn't perform as well. Like I said it's all not really that close.
 
In all attempts, W2 blades have high hardness + fine grain (easily dry shave & no problem whittle dry hardwood/oak). If there are free carbon avail next to Cr & V, well it would alloying up. Or excess carbon would form & precipitate into cementite. So tempering shrunk/shorten martensite crystal, hence cementite would form - just from precipitation alone (within the grain). My 325F tempered purpose was to see how much cementite formed prior to precipitation (~ 0.93 - (0.6 - 0.05)) and even at grain (0.5 to 2um grain size) boundary, edge wear resistance should be there. In cutting little cardboard, it was plain dulled (not microchip under a loupe view). It just didn't reflect wear resistance attribute of high carbon steel.

While Aldo recent 1095 is great - excellent wear resistant every time (the whole 3 times total - hahaha).

Willie71 said:
Bluntcut, looking at the HT cycles you did, it's possible on tests 2,3,4 that the carbon is in the grain boundaries. My second thought is a 325f temper should leave the w2 very hard/brittle. Is the edge possibly microchip ping causing the loss of edge?
Click to expand...
 
Yes Stuart, put the carbon where You want trough the normalizing/refining steps and then that thing will become HARD!!! Also will hold a keen edge with surprisingly high hrc..
Of course being hypereutectoid we must be sure of our heating source...68,5 HRC is very high, but we need it (and then adjust with temper)... because if we overshoot the temperature we'll get lower number togheter with poor edge stability due to RA...in doubt i find better to undershoot temp. if i don't have a good thermocouple.
 
Willie, I think (read into that I KNOW) you are RIGHT....and I WAS WRONG. Gotta write that down for my wife (Stuart was wrong on 12:19 June 10, 2014). Willie I owe you, and indeed all of you, an apology!!! Looking more CLOSELY at the stupid little picture with the blurred out words and numbers.....it was showing Ms....not Mf. I quote, "A characteristic feature of martensite transformation in steels is the transformation from austenite into martensite is NEVER COMPLETE." (Steel Heat Treatment Handbook edited by George E. Totten, Maurice A.H. Howes). There is a graph that shows amount of RA, and the Ms/Mf curve. The Ms start is at 0 celcius, and the Mf is at -100 celcius, and at -100C only 80% is martensite....20% left in RA. Alloying elements can raise/lower this number. Nickel lowers the amount of RA. However, this is where it gets confusing. He says "Cooling below Ms does not lead to further transformation or lower the amount of RA". Notice he said Ms....not Mf. And Ms being freezing temp of 0 celcius. But I think that may be a typo, because he says this...."A little below the point Ms, slower cooling enhances the transformation of austenite to martensite. The ability of austenite to isothermally formate martensite at temperatures a little lower than the point Ms is realized here. At temperatures close to the martensite finish temperature Mf but within the interval Ms–Mf, when a rather significant amount of martensite has been formed already, acceleration of cooling favors a more complete transformation." I'm pretty sure, after reading that, that the statement "Cooling below Ms does not lead to further transformation or lower the amount of RA" should read Mf....not Ms, because he said that cooling below Ms enhances austenite changing to martensite!

A lot to learn, for sure. Thanks Willie! I'm glad you're here to help "edumicate" me!!!
 
Hey, I'm just starting to get a handle on this stuff. :thumbup: i come from an academic background, so the science interests me. I am looking foreword to meeting Kevin Cashen this weekend and getting some references from him. I am really intrigued with nickel right now. My 15n20 is performing WAY better than it should based on the other elements. I think nickel has been overlooked.
 
Don Hanson III said:
Thanks man! I've never done spheroidizing on W2, just three normalizing cycles. I also use a vertical forge and not a oven, I know that goes against the 'experts' but it sure works for me. Sometimes I think we can over-think this stuff... I got into this W2 for the hamon, but the high performance was a good surprise. I also got W2 (cutoffs) from the same source I got the huge volume of round stock that didn't perform as well. Like I said it's all not really that close.
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Don, did you ever have your supply analyzed to know the exact composition? I wonder what your carbon and alloying percentages are?
 
Willie71 said:
Don, did you ever have your supply analyzed to know the exact composition? I wonder what your carbon and alloying percentages are?
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Russ Andrews had a piece of the 2" rd bar analyzed, results below. I was told all the round stock was from the same melt and I believe it because it all acts the same. Had some square/rectangle stock that wasn't as good.

C .95,
Mn .22,
V .19,
Cr .15,
Si .23,
Mo .013,
Ni .08,
Cu .14
 
samuraistuart said:
Willie, what's going on with the 15n20? Higher Rc numbers than expected?
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I am finding the toughness and edge holding are exceptional for a steel that has so little carbon. I can go to Rc62 without chipping in kitchen, and Rc60/61 for skinners. Even at 60/61 with 0.010 edge at 15deg, they have been slammed into bones without damage. The edge holding is about equal to O1, maybe just a bit less.
 
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