Heat Treating W2

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Randydb

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Sep 27, 2014
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Hi,
I'm a noob who has built his own 2x72 and ground bevels on about a dozen knives. Also have done lots of handles on knives and sheaths.

I have a local knife maker do my HT who does a ton of stainless steel knives for the meat processing industry, carving, and skinning. He has a great set up including a digital kiln and plasma cutter. Tons of experience with stainless like AEB-L and s35vn.

Recently I brought him some W2 blades I ground from New Jersey Steel Baron. He hasn't done W2 before and got info on HT from the net but it didn't work. Came out at 22HRC.

I don't know crap about HT in general. But the little I know is that W2 is better quenched in a brine and needs to lose heat fast when it is quenched.

Could someone please share a reliable heat treat process that I can pass on to Mike for when we try again on these W2 blades? Please note he does have a digital kiln. Thanks.
 
The stickys has a lot of W2 info in the Metallurgical Sticky. If you use the custom serach engine and search W2 HT you will get a lot more. Larrin also wrote a paper on it.

Also's W2 is 100% sheroidal. It needs a pre-heat at around 1650F with a 15 - 20 minute soak, and a coolinbg before the final HT. Done right, it will hit Rc 66-67 as quenched.
 
There is a ton of information on this site if you search it. My New Jersey Steel Baron W2 recipe is down in the shop, but is approximately this (I am making chef knives):

Normalize 1650F 20 min air cool and then repeat at 1500, 1450, 1425 for 10 min and air cool
Austenize at 1460 for 10-15 min quench in Parks 50
Tempering at 375 2x for 2hrs yields 62-63HRC
 
Stacy E. Apelt - Bladesmith said:
The stickys has a lot of W2 info in the Metallurgical Sticky. If you use the custom serach engine and search W2 HT you will get a lot more. Larrin also wrote a paper on it.

Also's W2 is 100% sheroidal. It needs a pre-heat at around 1650F with a 15 - 20 minute soak, and a coolinbg before the final HT. Done right, it will hit Rc 66-67 as quenched.
Click to expand...

I have read a lot of Larrin's stuff. Right now I feel like I am learning a new language! Some I get, but a lot I don't.

I know there is a ton of information....my problem is I don't know anything about HTing so I see a ton of information that isn't all the same and I don't know how to glean out the good stuff.

Like processes can be so VERY DIFFERENT and I don't know which is right.

I read Staceys "preheat to 1650F with 15-20 minute soak" then Carterwhopkins says the following.

Carterwhopkins said:
Normalize 1650F 20 min air cool and then repeat at 1500, 1450, 1425 for 10 min and air cool
Austenize at 1460 for 10-15 min quench in Parks 50
Tempering at 375 2x for 2hrs yields 62-63HRC
Click to expand...

Is Normalizing and preheat the same thing? I also have read tht Rc around 66-67 is possible, but carterwhopkins is getting less?

I also came across the following which is supposed to be Don Hanson's W2 HT and he seems to be a W2 expert.

- put the blade in the kiln cold, with a chunk of mild steel, ramp up to 1425 to 1450, (depending on the thickness of the blade) minimum soak time is 5 minutes.
- quench in warm oil/brine(unless using Parks 50, ).

- The most important part is to get the temp of the blade from 1425/1450 to about 600 in 1 second! So you have to have your kiln and quench tank oriented to where you can do it in one smooth motion.

I have come across other ones that vary from these ones. I just want something that is easy to follow and if we follow it right I am going to get a good result. Is Carterwhopkins process a solid one to follow?

I also came across and read another thread https://www.bladeforums.com/threads/w2-heat-treating-results.1649533/ .

Another similar process? is this to deal with the possible problems in the past thread?

Normalize at 1650 hold for 10 min, cool to black
Preform DET anneal by heating to 1400 or 1460 (not sure) furnace cool
Heat to 1475 hold 10 minutes quench in p50
 
Also this guys process
I do 3 normalizing cycles on the blade before doing the quench.

  1. Hold at 1550°F for 10 minutes then take out and cool in still air
  2. Hold at 1450°F for 10 minutes then take out and cool in still air
  3. Hold at 1350°F for 10 minutes then take out and cool in still air
Hardening:

  1. I’ll hold the knife at 1460°F for 8 minutes, then quickly do a fully submerged uninterupted quench in Parks 50 heat treating oil.
Tempering:

  1. I do two tempering cycles at 450°F for 1 hour on each cycle. Now she’s tough and ready to go.
How do these different processes and temperatures effect the final product? One tempers at 450f and another tempers at 375f. Does it matter?
 
Randydb said:
Also this guys process
I do 3 normalizing cycles on the blade before doing the quench.

  1. Hold at 1550°F for 10 minutes then take out and cool in still air
  2. Hold at 1450°F for 10 minutes then take out and cool in still air
  3. Hold at 1350°F for 10 minutes then take out and cool in still air
Hardening:

  1. I’ll hold the knife at 1460°F for 8 minutes, then quickly do a fully submerged uninterupted quench in Parks 50 heat treating oil.
Tempering:

  1. I do two tempering cycles at 450°F for 1 hour on each cycle. Now she’s tough and ready to go.
How do these different processes and temperatures effect the final product?
Click to expand...
The Rc post heat treat is 67+/-....I aim for and get 62-63 post temper. I do think it is important to take the blade to 1650 as Stacey and I do, then 3-4 lower temp cyclcles. 1460-1475 and hold for at least 10min then quench in Parks.
 
If you're having problems heat treating W2 from Aldo, either you or your heat treater can contact Ed Braun at NJSB to help trouble shoot the problem.
The way the steel is annealed can make a huge difference in how well it hardens. If it's heavily spheroidized like the product from NJSB it requires a fair amount of heat to break them up. If you're forging it, that takes care the problem but if not, you may have to normalize it at 1750 and may have to use a little more heat to austenitize it. Bottom line is you or your heat treater will probably have to run a variety of coupons to find the protocol that works best with your equipment.
 
Carterwhopkins said:
The Rc post heat treat is 67+/-....I aim for and get 62-63 post temper. I do think it is important to take the blade to 1650 as Stacey and I do, then 3-4 lower temp cyclcles. 1460-1475 and hold for at least 10min then quench in Parks.
Click to expand...
Your temper at 375 takes the Rc down from 67ish to 62-63. Will tempering at 450f make the hardness slightly different?
What Robert says about normalizing at 1750 comes from that other thread I posted. What we normalize at 1750 and it isn't the w2 that was bad from them....will it wreck the steel or will I just be doing a step I didn't need?
 
Randydb said:
Your temper at 375 takes the Rc down from 67ish to 62-63. Will tempering at 450f make the hardness slightly different?
What Robert says about normalizing at 1750 comes from that other thread I posted. What we normalize at 1750 and it isn't the w2 that was bad from them....will it wreck the steel or will I just be doing a step I didn't need?
Click to expand...
Check out the temper charts...I find I need to go lower than many of the published temps to get my 62-63. I have not tried to temper at 450, w/o looking at a chart, I would guess 59/60??. You need to test a bunch of samples and record your findings...I have never gone above 1650 and I have gotten uniform results for 2+ years with NJSB W2, and multiple orders...I have not experienced a bad batch as some have. Break some of your test coupons and take a look at the grain structure under magnification. I assume you or your heat treating guy has a hardness tester.
 
Yes, he has a hardness tester. I will pass your process on to my guy carter. You obviously have had consistent good results and that will give us a good chance at success.
Thank you.
 
Randydb said:
Yes, he has a hardness tester. I will pass your process on to my guy carter. You obviously have had consistent good results and that will give us a good chance at success.
Thank you.
Click to expand...
I will double check my recipe tomorrow when I'm in the shop and send you a msg.
 
The reason I give 1650 as the first step is that spheroidized W2 needs at least an extra 100° more than the usual 1550/1450/1350 normalization cycles. As pointed out, some folks start at 1750 to be sure the spheroid structure is dissolved.
 
Randydb said:
- The most important part is to get the temp of the blade from 1425/1450 to about 600 in 1 second! So you have to have your kiln and quench tank oriented to where you can do it in one smooth motion.
Click to expand...
While it is wise to have kiln and quench tank oriented to where you can do that in one smooth motion , to GET blade from 1425/1450 to about 600 in 1 second depends on characteristics of quenching medium .......not on transwer speed from kiln to quench tank . After all this years on blade I learn this..IF you are not sure of condition of steel you have , start normalizing proces with forge temperature of that steel...that way you can not miss .
 
Correct - the drop rate starts when the steel hits the oil. The transfer time is not an issue as long as it is done in a smooth transfer from oven to nearby quench. On swords, you sometimes have to quickly ( and safely) walk outside to the quench tank.

Starting at the 1750-1800F range is a safe practice if you are unsure of the steel's condition, or if a first quench did not harden at all.
 
Thank you all for your generosity and input here. It has been a wealth of information and leaves me reasonably sure we will get reasonable results on the next try.

Now my curiosity is getting to me. Even though W2 is a "water quench" steel almost no one uses straight water because it is a "harsher" quench. Majority use Parks 50 which "gives a more uniform, less severe quench than water." I came across an 11 page thread from 2011 about using canola oil as a substitute for Parks. Also other people talk about using a salt brine successfully. But then I read that the brine actually speeds up the cooling speed and increases chance of cracking?

My question is, are these guys splitting hairs between parks and canola? Also, where does brine fall with these mediums?

I also realize these guys are after hamons....that is in my future somewhere. I love the look of hamons. I read some threads where posters claimed that water/brine quenches produced better hamons and they felt it was worth the risk of cracking the odd blade.

Right now I just want a hard, durable blade and to improve my grinding skills. Later I want hamons!
 
Stacy E. Apelt - Bladesmith said:
Correct - the drop rate starts when the steel hits the oil. The transfer time is not an issue as long as it is done in a smooth transfer from oven to nearby quench. On swords, you sometimes have to quickly ( and safely) walk outside to the quench tank.

Starting at the 1750-1800F range is a safe practice if you are unsure of the steel's condition, or if a first quench did not harden at all.
Click to expand...
Okay, our first quench didn't harden at all....so we should probably start normalizing at 1750F?

So would this be a reasonable normalization sequence? I am unsure of the amount to drop the temperature each time, and the lowest temperature needed. Also number of cycles needed.

1750F -hold 20 min - air cool to black
1600F -hold 10min - air cool
1450F -hold 10min -air cool
1350F -hold 10min - air cool
 
YES. THIS ^. Even slightly hotter as in 1800°F for the normalizing heat. This latest batch of W2 is extremely heavily annealed from the factory. If you are forging the blade into shape, there is no need for such a high normalizing heat. If you're just doing stock removal, I would modify your HT slightly. There has been a lot of discussion as to the issues with the latest W2 batch. Previous recommended heat treatments don't really apply to it.

1800°F - hold 20 min - air cool to black (this is the normalizing heat and a lot of makers are reporting that the usual 1650F isn't hot enough for this batch)
Thermal cycle 3x at 1500°F - hold 10 minutes each cycle - air cool to black (1600F is another normalizing heat...not needed. 1450F is OK if you want to do that 3x. 1350F I don't know why people are recommending that temp for thermal cycling. That is re-spheroidizing temp and is too low for the phase change you need for grain refinement. Just do ~1500F 3x or 1450F 3x)
To harden, this will require a bit of experimenting to get the max hardness, but you might start at 1450F, soak 10 minutes, quench in fast oil. do a test coupon. If it's too low, try 1475F, and then 1500F. There will be a temp at which hardness peaks. With this batch of W2...it may be closer to 1500F). Then temper as desired...which again will depend on your as quenched hardness. 375F should be ~63-64HRC.
 
Looks good. Some folks quench from the 1450 and 1350 steps to assure fine grain.

After those steps you do the final quench at the austenitization target.
 
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