Aldo's W-2 steel

[Tom Lewis]

Maybe 20 years ago I bought a lot of W-2 steel from Aldo. I could not get it to harden, so I set it aside and pretty much forgot about it. The other day I was looking At Aldo's site and saw his Heat Treating recipe for W-2 steel.
I cut three coupons off three W-2 bars I had. I used my Paragon oven and heated them to 1650F for 12 minutes, took them out and let them cool. Then I put them back in at 1500F for 122 minutes and took out and let cool. Finally I put them in at 1,350F for 12 minutes took out and let cool to room temperature.
I hardened by heating to 1475 F for 10 minutes and quenched in Park's 50.
After they had cooled down I tried a file test. The file did not skate off the steel. The file cut into the steel. I put one of the pieces in a vice and beat on it with a large hammer. After a lot of hits, The steel bent, then broke. The grain was very fine. Then I ground the de-carb off the last two pieces and tested with my Rockwell tester. One piece tested 49RC and another piece tested 51RC.
Using Aldo's recipe the W-2 did get harder, but not hard enough. That was disappointing.
This morning I was going to heat treat another piece of steel and decided to quench the W-2 in water. I heated two pieces of W-2 to 1475F for ten minutes and quenched in water. I did not do any normalization cycles with this steel. When the steel cooled down, a file skated across the steel. On the Rockwell hardness the steel was 63Rc. I put a piece in a vice and tapped with a hammer and it broke. The grain looked as fine as the steel I had cycled.
Back in 1991 I took an ABS Damascus class with ABS Master Smith Charles Ochs. He used water to quench all his blades. I also used water for awhile but every so often I would get a blade that cracked so I started using oil and then when I found out about Parks 50 I started using that.
I hope this information will help someone, and if any of you have experience hardening Aldo's W-2 steel I hope you will share your experience.

 

[Michael Black]

I buy my W2 from NJSB and have had great success using their recommended heat treat instructions, although I don't remember exactly what I use off the top of my head. It's programmed into my kiln. I've only ever hardened in Parks 50 with no issues, despite it being a water quenching steel. Then again, I have only been buying from them since 2016, so maybe you got a bad batch 20 years ago. I wonder if they have records that go back that far to see if you can find out more about that particular steel batch.

 

[oldschool45]

This blade is Aldo's W2 I did a few days ago from a batch purchased earlier this year maybe later last year. . Heat treating; 1465'f soak for 8 minutes quench in Parks 50. Temper 300'f 2x2 hours been getting a hair over 63 Rockwell with that recipie.

 

[Tom Lewis]

Oldschool45, did you normalize the W-2 before you heat treated it?

 

[Stuart Davenport Knives]

A 200°F temper on fully hardened W-2 should read WELL over 63HRC. That should be basically "as quenched" hardness of 66HRC+.

It has been a hot minute since I've used Aldo's W-2. Stock removal, no forging. But I can tell you what another very highly experienced maker told me about Aldo's W-2 back around 2019 or so.

He and a friend, again just stock removal, no forging, could not get it to harden correctly. They tried the industry standard normalizing heat of 1650°F and didn't get any better result. They thought it might just be extremely spheroidized from the mill, which has been a problem with NJSB steel for some time, so they bumped up the normalizing heat to 1900°F and that solved the problem. I don't recall the follow up thermal cycles they did, but the problem was indeed the steel was so heavily annealed it required that much heat to break up the very coarse spheroidized carbides.

I don't think makers that forge W-2 see too much of a problem, due to the fact the steel is undergoing forging heats, whereas stock removal doesn't.

If it were me and I had to use that W-2, I would try what MG and his buddy told me about the high normalizing heat. Try 1900°F for 10 minutes, followed by a cycle or two around 1500°F, then harden around 1475°F for 8-10 minutes. A Parks 50 quench "should" get you 66HRC+ as quenched. If that solves the problem, you can then experiement with different thermal cycles and even DET anneal, if you like. 1350°F is too low of a thermal cycle to do anything except start to spheroidize the steel. If that's the goal, then do a proper spheroidize anneal.

 

[oldschool45]

Oldschool45, did you normalize the W-2 before you heat treated it?

Yes, I do stock removal but because of the previous concerns with Aldo's W2 and wanting the best "canvas" for a hamon I do the normalizing cycles.
Off hand 1st 1650F for 15 minutes> cool to black> 2nd 1500F for 15 minutes> cool to black > then 3rd and final 1350F for 15 minutes. > Ready to heat treat.
I did recently make a tomahawk head out of quarter inch W2 and skipped the normalizing cycles. Didn't Rockwell the head but it turned a Kevlar K-pot into a pasta strainer right nicely.

 

[oldschool45]

A 200°F temper on fully hardened W-2 should read WELL over 63HRC. That should be basically "as quenched" hardness of 66HRC+.

My bad and I edited my post 300'F temper 2x 2hours.
Is tempering that low even effective? I like to run W2 HARD but I don't want it to be that glass brittle.

 

[Stuart Davenport Knives]

No, I don't think 200°F does very much. Even with a 300°F temper, I would expect 65HRC.

 

[Stacy E. Apelt - Bladesmith]

Until W2 getas a temper around 350°F the hardness doesn't drop much at all. Assuming a proper quench, 300° is barely off as-quenched, and 350° yields Rc63/64.
I use 400°F and get Rc62/63.
HARD is only part of the equation. Glass is harder than steel, but makes poor knives. It takes enough tempering to change the brittle martensite to tempered martensite so it does not chip or break. A 200°F temper might keep it from cracking on its own, but would be far too low. I personally think 300°F is too low for a W2 knife

 

[Tom Lewis]

Stuart, thanks for the heat treat suggestion. Today I tried it.
I heated to 1900 degrees for 12 minutes, let it cool. Heated to 1500 degrees for 12 minutes, let cool. Then 1475 for ten minutes and quench in Parks 50. The W-2 did not get hard. A file would cut it and when I put it in a vice and beat on it with a large hammer the steel bent and would not break.
I guess if I want to use this steel I will need to water quench.

 

[Stuart Davenport Knives]

Wow. That's just not acceptable. Even with your water quench, those hardness numbers are easily 2-3 points too low. Lot's of reported problems with W-2 these days. It is a finicky steel to be sure.

 

[Keanen]

Stuart, thanks for the heat treat suggestion. Today I tried it.
I heated to 1900 degrees for 12 minutes, let it cool. Heated to 1500 degrees for 12 minutes, let cool. Then 1475 for ten minutes and quench in Parks 50. The W-2 did not get hard. A file would cut it and when I put it in a vice and beat on it with a large hammer the steel bent and would not break.
I guess if I want to use this steel I will need to water quench.

I would trie a 1650 normalizing then a grain refining step at 1450 then a D.E.T anneal at 1390 soak for 30 then cool at 670 degrees to 1200 then austenitize at 1475 soak for 10-15 depending on stock thickness quench into room temperature parks 50.Hope this helps