W2 issues

Joined
Sep 10, 2005
Messages
513
So after the threads a while back about Aldos W2, and now that i have a hardness tester I ran some coupons on the W2 I had. Somewhere around 20 bars of 1, 1.25 and 1.5" that Ive bought over the last few years. I hadnt really used any of it before. My initial coupons were all in the 30-40hrc range. Talked to NJSB who passed me off to their expert. Followed his HT that he wanted (1750, 1550 cycle, then austenize and quench in P50). Still got same HRC. They said they would replace half of what i have, 10bars of the 20, because some were bought 3-4years ago. So, since im going to be stuck with 10 bars, i decided to test them all before sending back any that might be good. I think 5 hardened to about 60 when i think they should be closer to 65. I did a 15 mins soak 1750, 15 at 1550, 1500 to quench in P50.
Also, i verified my kiln temp with 1500*tempilaq. Verified tester with a 64hrc test block. On top of that, I put in 2 coupons each of 1084 (low 60s), 1095 (65ea), and 80CRV2(62 ea). This tells me that the problem is the steel, not my HT unless theres something Im doing wrong.
 
Your 1084 numbers seem a bit low also, if I’m not mistaken you should be able to get around 65 pretty easily, especially with p50 I would assume. Are you forging or doing stock removal?
 
the thermal cycles you listed will produce decarburization.....grind past that before austenitizing...
and after...then test hardness..
 
Your 1084 numbers seem a bit low also, if I’m not mistaken you should be able to get around 65 pretty easily, especially with p50 I would assume. Are you forging or doing stock removal?
Forge, but these were just cut off the bar stock as coupons to test
 
From what I understand it's because of the way some of it was coming from the mill. The stuff is so heavily spheroidized that you need to forge it or normalize it at 2000 degrees to reset the steel to a hardenable state.
 
Forge, but these were just cut off the bar stock as coupons to test

From what I understand it's because of the way some of it was coming from the mill. The stuff is so heavily spheroidized that you need to forge it or normalize it at 2000 degrees to reset the steel to a hardenable state.

That’s what I was thinking, maybe try heating a coupon like you were going to forge it with both 1084 and w2 then follow your normal process of thermal cycles, quench then grind past decarb and test again and see if you get different results compared to your first tests, I forge 1084 from njsb and have no problem skating a file that I know is 62 hrc after quenching and I’m only quenching in warm canola oil.
 
Dov you have the alloy content for the batches of steel. The carbon content could be on the low end as well as other variations in the alloy. Quenching should occur after the soak at the hardening temperature. What are you using to quench? W-2 is a water hardening steel, the denser the quenching medium the slower the cooling rate which can reduce the as quenched hardness.
 
the denser the quenching medium the slower the cooling rate
That's not right. Canola oil is less dense than water and gives you a slower quench. Brine is denser than water, also a slower quench I think? Speed of the quench is due to a lot of factors
 
Yes, density isn't the deciding factor. It is a combination of heat transfer properties and mainly the vapor jacket.
The reason brine is better than water ( even though it is slightly slower) is the salt makes the boiling point of water higher and thus collapses the vapor jacket faster. Commercial oils have various ingredients that make the quench slower or faster. Water is an unpredictable quenchant because of the vapor jacket and should only be used to quench aluminum, titanium, and brass alloys.
Oils come in blends from fast to very slow. The temperature of the quenchant is also important. Too cool and it doesn't work right, too warm and the vapor jacket doesn't collapse right.
Water and brine are used at 100°F
Parks #50 is used at 60-90°F. Most other oils are used at 120°F.
Molten salt is used at 400°F
Lead can melt, depending on what is added to it, between 250°F (pewter) and 620°F (pure lead). In old time Sheffield and other places industrial shops used a 600° lead quench because it advantages for straightening and toughening the blades. The lead greatly shortened the life and sanity of the workers.

The fastest quenchants are strong hot solutions of caustic soda and water. These are very dangerous for home users and should never be used for knives.
Molten salt or lead is a very fast quenchant because no vapor jacket forms. Lead is still used in some industries and shops, but isn't really a good idea for the home knifemaker.
 
1750f normalizing
1550f thermal Cycle
...

1500f Austenizing.

No sub-critical anneal or DET?

I feel like you're missing the "coup de grace"

Gotta spread that carbon out more after the thermal Cycle before Austenizing.
 
Is the caustic soda method the old Red Devil lye quench that we have heard about? Ten or so years ago, som said that a guy tried to pass the ABS perforce test using a low carbon blade quenched in lye.
Yes, density isn't the deciding factor. It is a combination of heat transfer properties and mainly the vapor jacket.
The reason brine is better than water ( even though it is slightly slower) is the salt makes the boiling point of water higher and thus collapses the vapor jacket faster. Commercial oils have various ingredients that make the quench slower or faster. Water is an unpredictable quenchant because of the vapor jacket and should only be used to quench aluminum, titanium, and brass alloys.
Oils come in blends from fast to very slow. The temperature of the quenchant is also important. Too cool and it doesn't work right, too warm and the vapor jacket doesn't collapse right.
Water and brine are used at 100°F
Parks #50 is used at 60-90°F. Most other oils are used at 120°F.
Molten salt is used at 400°F
Lead can melt, depending on what is added to it, between 250°F (pewter) and 620°F (pure lead). In old time Sheffield and other places industrial shops used a 600° lead quench because it advantages for straightening and toughening the blades. The lead greatly shortened the life and sanity of the workers.

The fastest quenchants are strong hot solutions of caustic soda and water. These are very dangerous for home users and should never be used for knives.
Molten salt or lead is a very fast quenchant because no vapor jacket forms. Lead is still used in some industries and shops, but isn't really a good idea for the home knifemaker.
 
Some of the issue (but not all of it) with the W2 is that it was so heavily annealed at the factory. I personally talked with a few different makers who have forgotten more than I know about heat treatment that said the latest W2 from Aldo required a 1900°F normalizing heat to break up the carbide bonds that result from the heavy annealing. (rather than the 1650°F it should take). That's why guys who are forging the W2 aren't having much of an issue. Guys who are doing stock removal are getting sub standard hardness results. There is also the issue of a somewhat low carbon % with this W2 compared to it's data sheet specs. But that's another topic. I would recommend a 1900°F normalizing heat to start with. Then thermal cycle 3x at 1500°F. I would not worry about performing a DET anneal on this steel at this stage. The fewer the variables the better. Once you get the numbers where you want them, maybe a DET anneal can be thrown in. Your austenitizing temp will need some experimenting as well, but try 1500°F with a short soak and see where that gets you. Just always make sure that prior to hardness testing that the scale AND decarb layer have been removed.
 
If you are stock removing there is no need to normalize prior to HT, even w2 annealed to 13rc should get rock hard if quenched in fast oil from 1450-1500 as long as you dont soak too long. This is assuming the steel was processed correctly at the mill.
1750 is too high for a simple steel like w2 IN MY OPINION. I usually normalize 100-120°F above my austemp with simple steels, I mean you forged it HOT right?
After forging I generally heat to 1560 and air cool then 2 or 3 cycles of 1410 to refine grain. Then I either anneal or directly harden from 1465 into parks50.
The new w2 njsb sent me hardened perfectly from 1465 cut off the bar with no normalizing, and also responded well to my above procedure after forging. The first stuff they sent me I spent 8 months trying to figure out.
I HT in a drum forge with thermocouple and use a grizzly benchtop tester.
I'm no expert or claim to be, this is just from my hands on experience and trials. I am comfortable now with my procedures and my steels in my shop with my tools.
-Trey
 
If you are stock removing there is no need to normalize prior to HT, even w2 annealed to 13rc should get rock hard if quenched in fast oil from 1450-1500 as long as you dont soak too long. This is assuming the steel was processed correctly at the mill.
1750 is too high for a simple steel like w2 IN MY OPINION. I usually normalize 100-120°F above my austemp with simple steels, I mean you forged it HOT right?
After forging I generally heat to 1560 and air cool then 2 or 3 cycles of 1410 to refine grain. Then I either anneal or directly harden from 1465 into parks50.
The new w2 njsb sent me hardened perfectly from 1465 cut off the bar with no normalizing, and also responded well to my above procedure after forging. The first stuff they sent me I spent 8 months trying to figure out.
I HT in a drum forge with thermocouple and use a grizzly benchtop tester.
I'm no expert or claim to be, this is just from my hands on experience and trials. I am comfortable now with my procedures and my steels in my shop with my tools.
-Trey
Those honyaki gyutos you make are insanely gourgous, and nice and thin. Love your work Trey, very clean.
 
Those honyaki gyutos you make are insanely gourgous, and nice and thin. Love your work Trey, very clean.
Thanks bud, almost didn't comment here . Dont want to start any controversy, but normalizing steel that came from a mill before hardening is silly to me. Lots of misinformation about. If you buy good steel from a good mill it should be processed well and ready for hardening.
We anneal to PREPARE for hardening. Do not be afraid of hardening annealed steels.
I anneal all my honyaki before hardening unless I WANT to see the carbide segregation banding. Then I quench from pearlite.
-Trey
 
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