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NJSB W2 and 52100 Heat Treat

Cypress Creek Knives

Cypress Creek Knives

CCK
Knifemaker / Craftsman / Service Provider
Joined
Dec 15, 2010
Messages
644
Good morning everyone,
I was wondering if anyone has nailed down a solid heat treat for both W2 and 52100 from NJSB. I have read most of the old threads and discussions about the spheroidized steel and how NJSB may or may not have solved that issue. I'm curious to know if anyone has found a solid heat treat for these steels in 2022. And specifically if I need to worry about a high normalization cycle to break up the spheroidized steel.
 
Dunno, but I just got some the other day, and am in the process of making a knife.

I'll let you know what I get when I go to HT it.
 
A.McPherson said:
Dunno, but I just got some the other day, and am in the process of making a knife.

I'll let you know what I get when I go to HT it.
Click to expand...
I look forward to hearing your results. I may end up making a few test coupons and see what I come with, but I would prefer to save myself the trouble
 
OK, let's learn what we are dealing with:

Spheroidizing of high carbon steel is a method of prolonged heating at a temperature below the eutectoid temperature (around 1250°F/680C). By heating at this temperature pearlite, which is the lowest energy arrangement of steel, gets converted to ferrite and cementite. The graphite content of steel assumes a spheroidal shape after spheroidizing and after prolonged heating the pearlite layers are broken down and spherical lumps of cementite, or spheroidite, are formed.

The structures in spheroidite are one thousand times larger than those of pearlite and are spaced further apart. This means the spheroidite steel is extremely ductile.

Now that we know what the issue is, this is how to normalize it to change the spheroidite into a hardenable structure:

To normalize a hypereutectoid steel (high carbon), you need to dissolve all the carbides, cementite, pearlite, and spheroidite at a high enough temperature. You want to get it to a fully austenitic structure. This takes time and a high enough temperature above the Acm point. For heavily spheroidized steels start the normalization at 1650°F/900°C. Hold it for 15-20 minutes at that temperature. To normalize a spheroidized steel, a HT oven is the best method. You can do it in a forge with so-so results, but it is a crap shoot.

After dissolving all the other structures into austenite, you are ready to refine the grain by multiple cycle drops in temperature. I recommend 1650 - 1550 -1450- quench.

The best normalizing procedure for fully spheroidized steel will be:
Heat to 1650°F/900°C and hold for 15-20 minutes - cool to black
Heat to 1550°F/840°F and hold for 10-15 minutes - cool to black
Heat to 1450°F/790°C and hold for 10-15 minutes - Quench in Parks #50 or equivalent
Cool to room temperature (caution, the steel is very brittle at this time)

At this point the steel will be fine grain and ready for you to do your final HT at the exact target temperature for the steel.
 
I see absolutely nothing wrong with asking if someone has a good heat treating recipe. I don't consider that cheating at all. There is no need to re-invent the wheel.
One of the main purposes of this forum is to help each other.
There are literally thousands of ways to normalize, etc. If someone has a method that works I see nothing wrong with asking for it. That is what heat treating books like Larin's does.
I mean if someone asks for a good epoxy glue is he going to be told, "Don't cheat yourself, find out for yourself."
 
its ironic that as I strolled through the other topics in the topic area I see someone revisited How to heat treat 52100 by Larrin
 
I think the real issue with the steels mentioned isn't necessarily a heat treat protocol, but the spheroidizing that goes on in that mill from Europe. I haven't used those two NJSB steels in quite some time, so I can't personally say for certain that things have gotten better. But it would be a simple test if one were inclined. Let's just use the NJSB 52100 as an example. It can apply to the W2 as well, remembering tho that W2's hardening temp is lower.

Take an bar as received and harden it. 1525°F 10-15 minute soak, fast oil quench, check the as quenched hardness. It should read 66HRC+. If so, I would suspect that the mill revamped it's annealing.
If the steel did NOT reach 66HRC+ as received, try normalizing the steel at 1700°F, then harden, and try as quenched hardness again.
And if the steel does not reach 66HRC+ after that normalizing and hardening, try 1900°F for a normalizing temp, maybe a grain refine at 1500°F, and harden from there.

Of course, anti decarb should be used on all heats, as that can throw off hardness results.
 
I’ve used a good amount of W2 from njsb recently and not had issues hardening, I’ve not had to do anything other then bring up to my desired hardening temps hold for 8-10 minutes and quench. So not sure if they have adjusted anything at the mill but I’ve not ran into issues hardening that alloy in the last year and a half to 2 years.
 
FYI, Larrin created a thread on this here, which includes my recent post here where I asked how to know what you're getting when you buy bars.

Alpha steels supply tells you that you don't need to do heat cycling, but won't tell you what has been done to the steel already.

I emailed NJSB and asked them what process has been done and they never bothered to reply to my email.

So yeah, a little frustrating.
 
A.McPherson said:
Joshua Fisher Joshua Fisher do you have a good protocol for getting a good hamon with NJSB W2?
Click to expand...
I use nuclayer clays, pre grind 70-80% before heat treating them clay the spine with about a heavy 1/16” thick layer of clay, If stock removal I go straight into hardening at 1465F and hold for 8-10 minutes and quench in parks 50 that has been pre heated to 70-80F
 
matto6 said:
Alpha steels supply tells you that you don't need to do heat cycling, but won't tell you what has been done to the steel already.
Click to expand...
The heat treating section on our website states the following:
"Condition: This alloy been properly annealed and is in the soft condition. You do not have to do any non-standard wasteful processes before heat treating. The steel must be heat treated to get to a hardened state. Follow the heat treat recipe and the steel will harden."

What additional information do you want added?

Chuck
 
Alpha Knife Supply said:
The heat treating section on our website states the following:
"Condition: This alloy been properly annealed and is in the soft condition. You do not have to do any non-standard wasteful processes before heat treating. The steel must be heat treated to get to a hardened state. Follow the heat treat recipe and the steel will harden."

What additional information do you want added?

Chuck
Click to expand...
HI Chuck,

Thanks for chiming in. I called and asked what exactly the annealing process was. The person I spoke to said they didn't know, and it's" whatever they do at the mill". I was looking to find out exactly what the process was.

Larrin Thomas's blog (linked to on my previous post) shows that a DET annealing process makes a significant difference in the end result in teams of the toughness / hardness tradeoff. It's not just about whether the steel "will get hard" but what toughness you have at that hardness. He proposes a very specific annealing process that has proven to have good results.

Given that 52100 seems to respond quite differently to different annealing processes, it seemed reasonable to ask what process has been performed aleady, so knife makers can decide whether they like that process or want to redo their own.

Thanks!
Matt
 
Joshua Fisher said:
I’ve used a good amount of W2 from njsb recently and not had issues hardening, I’ve not had to do anything other then bring up to my desired hardening temps hold for 8-10 minutes and quench. So not sure if they have adjusted anything at the mill but I’ve not ran into issues hardening that alloy in the last year and a half to 2 years.
Click to expand...
Joshua, are you stock removal or forging? I haven't used W2 in probably 4 years. Back then there were even more problems with that W2 than just how heavily annealed it was.

Also, Matt, regarding the annealing process done at the factory, I can pretty much guarantee that it is not a DET anneal, but rather an extended process anneal. Their goal is really to make the stuff as soft as possible for machining. Our goal as knife makers is to have the stuff in the best condition prior to hardening for knife stuff. And on that note, the DET anneal is hard to beat.

What I do with 52100, regardless of where it came from, is

Normalize 1700°F 20 minutes air cool
Cycle 1500° 10 minutes air cool
Cycle 1450° 10 minutes air cool
DET anneal 1460°F 20 minutes down to 1200°F at ~666° per hour
Harden: 1525°F 10 minutes P50 quench
Cryo
Temper 3x
 
Last edited:
Stuart Davenport Knives said:
Joshua, are you stock removal or forging? I haven't used W2 in probably 4 years. Back then there were even more problems with that W2 than just how heavily annealed it was.

Also, Matt, regarding the annealing process done at the factory, I can pretty much guarantee that it is not a DET anneal, but rather an extended process anneal. Their goal is really to make the stuff as soft as possible for machining. Our goal as knife makers is to have the stuff in the best condition prior to hardening for knife stuff. And on that note, the DET anneal is hard to beat.

What I do with 52100, regardless of where it came from, is

Normalize 1700°F 20 minutes air cool
Cycle 1500° 10 minutes air cool
Cycle 1450° 10 minutes air cool
DET anneal 1460°F 20 minutes down to 1200°F at ~666° per hour
Harden: 1525°F 10 minutes P50 quench
Cryo
Temper 3x
Click to expand...
Mostly stock removal but occasionally I will forge some of the njsb W2 and when I do I go through several cycles to refine grain and get it where I want before hardening.
 
Stuart Davenport Knives said:
Normalize 1700°F 20 minutes air cool
Cycle 1500° 10 minutes air cool
Cycle 1450° 10 minutes air cool
DET anneal 1460°F 20 minutes down to 1200°F at ~666° per hour
Harden: 1525°F 10 minutes P50 quench
Cryo
Temper 3x
Click to expand...
Thanks. Do you know any professional heat treat folks who understand this and would be able to perform this service?

I spoke with one (who is mentioned a lot in these forums) and he claimed DET is unnecessary, and he would just do a normal annealing process.
 
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