Freaky hamon, had to kill it

Wulf

Wulf

Joined
May 10, 2000
Messages
3,351
I banged out a little fighter the other day from some of Aldo's W2 and got some interesting results with the heat treat. I've been quenching this stuff in Brownell's Tough Quench which cools the steel just fast enough to harden the thinner sections. While longer soak times increase hardenability, anything thicker than 1/8 or 5/32 tends to just barely miss the nose in the Tough Quench.

The end result is that this stuff can produce some really interesting hamons. After hardening this latest blade, a quick polish revealed a pretty freaky one indeed. Unfortunately, the unhardened portion came a bit too close to the edge in a few spots, so I had to heat treat this one again, but not before taking some photos first.

First, here's a shot of the rough forged blade
integral_fighter1.jpg


And here's the freaky hamon
crazy_hamon1.jpg


crazy_hamon2.jpg


So who else is using this stuff? Care to swap heat-treat recipes? :)
 
Strange indeed. I think you were wise to re-do the HT. I would worry about all that islanding. W-2 is great for hamon with clay coat.Try it if you haven't already. I would go to a faster oil, though. The right quenchant is better than one thar just barely does the job. With a clay coat, water will work (if you are brave).
Here are some HT tips.
Forge around 1850F. Anneal at 1450F. Stress relieve at 1245F. (soak all of those for 15 minutes). Austenitize at 1550 for 10 min. Quench in #50 heated to 130F. Do not remove from the oil except to quickly inspect the blade,and do not let fall below 120F (Leave in quench tank until ready for oven.It should hold above 120F for 10-15 min.). Transfer to a preheated HT oven immediately without allowing to cool below 120F if at all possible (wipe it off and put in oven). A one hour snap temper at 350F is the minimum prior to cooling to room temp for inspection grinding. Do not do any grinding prior to the first temper - NONE ! Final temper at 400-450F depending on desired HRC target.
Stacy
 
That is a freaky hamon. In my experience W2 will give the most hamon activity, good stuff.

I austenitize at 1450f, quench in Park's #50 oil and temper at 450f. I also do the HT over if I don't like the hamon.

Good info from Stacy also.
 
Thanks guys.

Stacy, can you explain why I shouldn't let the steel drop below 120 or do any grinding before the first tempering cycle?
 
I grind my W2 blades clean with a freash 120 grit belt right after quenching to see the hamon. If I like it, it goes in the tempering oven, if I don't, it goes back to the forge with new clay for another round. I've always heard "temper ASAP" but I just take my time and have never had a blade crack. I also straighten blades right out of the quench, before tempering, when needed. I do believe a water quenched blade should be tempered ASAP but I use oil and have waited days to temper on a few occasions.
 
W-2 steel has a tendency to crack due to martensitic embrittlement prior to tempering. In a knife blade you will most likely get by with allowing it to go to room temp. But it MIGHT crack all by itself sitting there. If you go and grind on it to see the pretty metal, it MAY crack in your hands. These problems mostly occur when the austenitizion temps are on the high side()1575) and the soak is on the long side (15 min+).

The cure is prevention, use the exact austinizing temps for the W-2 alloy you have (it varies a lot and can run 1425F to 1575F, depending on the carbon content) and temper immediately after quench, preferably before it drops below 120F.

Sunfishman avoids these problems by quenching at a temp below what most knife grade W-2 should be quenched at. He sacrifices some hardness by getting a little pearlite in the mix, but avoids cracking.
Stacy
 
bladsmth said:
Sunfishman avoids these problems by quenching at a temp below what most knife grade W-2 should be quenched at. He sacrifices some hardness by getting a little pearlite in the mix, but avoids cracking.
Stacy
Click to expand...
Stacy, I'm going to strongly disagree here. Your info may be correct for other tool steels but not for W2. I have a tool steel data booklet on W2 from Bethlehem Steel that reads as follows:

Hardness series for water quenched, 1% carbon, 1" round W2:

Aust. temp. RC hardness

1375f................62
1400f................65
1425f................68
1450f................68
1475f................68
1500f................67
1550f................66
1600f................65

As you can see, for W2, as the temp goes up the hardness comes down. I find 1450f to be the ideal aust. temp. for W2.

RC hardness will be one to two points lower if oil is used for the quench. I have worked a lot with W2 in the last 5 or 6 years and my own testing follows the above very closely.

With that said, it is best to temper ASAP after quench.
 
sunfishman,
You are absolutely correct. When I glanced at the info I had on W-2, I looked at the low-C to high-C temps. I read the hardenability info backwards. The lower the carbon content ,the higher the quench temp. For 1% W-2 1450F is right on. Thanks for the correction.

The tempering info was related to high carbon content, so ,as you said,temper ASAP.

Again, sorry for the mix-up. Your data is based on years of experience, and the proper charts.

Stacy
 
Just back in from the shop. Much happier with the latest heat treat. The first time the patterns differed so much from one side of the blade to the other that it was pretty apparent the steel didn't harden all the way through in most spots. I can't say for sure what the temp was at austenizing as I'm heat treating in a forge with no pyrometer, using (gasp!) a magnet and my eyeballs to find the sweet spot (I hope Kevin Cashen isn't reading this - he'll scold me for sure :eek: :p). That said, this time around I let it get just a bit hotter and soaked it a little longer too. It seems to have improved the result.

Here are some shots after a quick cork belt/ etch/ flitz finish. The final polish should bring out a little more detail.

crazy_hamon3.jpg


crazy_hamon4.jpg


Another interesting observation is the curvature. When I originally profiled the blade the spine was dead straight. It isn't straight anymore... That's OK though - I rather like the curve. :)
 
I'm with Don on this stuff Derrick.


I love the blade and hamon you've got going now. Bringing it next week? Test knife??? :)

Tough Quench works real well on steels like W2. Park's is a bit faster, but one of the most wild hamon I've gotten as far as really pronounced shadowing (utsuri) and ashi, it was 1084 quenched in Tough Quench.

I've got some wild ones on the work bench now from W2 quenched in Park's though... :)

See you fellas next week! :D :thumbup: :cool:
 
Don mentioned a couple of weeks back that he gets that curvature when he quenches his W2 more than once. Kevin Cashen told me that you can quench W2 in Tough Quench, but you should heat up the oil and agitate the blade. He also said that because the thicker parts of the blade may miss the nose of the curve by a hair, you can get some really interesting quench lines even without using clay or edge quenching. Tai Goo said that he quenced those 2 W2 blades he posted recently in vegetable oil, but he was real careful about heating the blade to right at critical. Don.....don't you use Parks #50 at room temp for W2?
 
sunfishman said:
Stacy, I'm going to strongly disagree here. Your info may be correct for other tool steels but not for W2. I have a tool steel data booklet on W2 from Bethlehem Steel that reads as follows:

Hardness series for water quenched, 1% carbon, 1" round W2:

Aust. temp. RC hardness

1375f................62
1400f................65
1425f................68
1450f................68
1475f................68
1500f................67
1550f................66
1600f................65

As you can see, for W2, as the temp goes up the hardness comes down. I find 1450f to be the ideal aust. temp. for W2.

RC hardness will be one to two points lower if oil is used for the quench. I have worked a lot with W2 in the last 5 or 6 years and my own testing follows the above very closely.

With that said, it is best to temper ASAP after quench.
Click to expand...
Even with "slow" oil, this W2 that Don has comes out of the quench as hard as woodpecker lips. My limited experience is that a couple of 1 hour long quenches at 450 are still going to possibly leave you with an edge that is too brittle and will chip.
 
Wulf said:
Just back in from the shop. Much happier with the latest heat treat. The first time the patterns differed so much from one side of the blade to the other that it was pretty apparent the steel didn't harden all the way through in most spots. I can't say for sure what the temp was at austenizing as I'm heat treating in a forge with no pyrometer, using (gasp!) a magnet and my eyeballs to find the sweet spot (I hope Kevin Cashen isn't reading this - he'll scold me for sure :eek: :p). That said, this time around I let it get just a bit hotter and soaked it a little longer too. It seems to have improved the result.

Here are some shots after a quick cork belt/ etch/ flitz finish. The final polish should bring out a little more detail.

crazy_hamon3.jpg


crazy_hamon4.jpg


Another interesting observation is the curvature. When I originally profiled the blade the spine was dead straight. It isn't straight anymore... That's OK though - I rather like the curve. :)
Click to expand...
Hey Wulf....you said that the patterns were different on each side. Did you agiatate the blade side to side in the oil? I did that once and the side that got "swished" first blew off scale higher up on the blade.
 
No, I didn't agitate it at all. I did heat up the tough quench to about 150 though.

Nick, I do hope to include this among my test knives but I'm gonna be cutting it real close to get everything done. Just over a week away!
 
very interesting...


Don - if what I'm reading is correct...if you have re-done the heat-treat...there is no "residual" left over from the first one?

In other words...the 2nd heat-treat completely erases the effects of the first one?

Yes..I have something up my sleeve...




Also, I would like to add my "me too" to what Don and Nick have said. I do the same and get the same results. But I use Tough Quench with clay and it works perfectly - plenty fast, great hardness results. I imagine Parks #50 is better than normal tranny fluid (which is lousy at best for clay-coated blades - made that mistake once).
 
I use the tough Quench also. But I do heat it up to 150 degrees before quenching. I also have a long tank that holds 12 gallons of the quenching oil and will set the blade in the oil at the back of the tank and slowly slide it towards the front of the tank. This keeps the oil circulating around the knife blade.
 
Good lookin hamon Wulf.

Joe, I do use Parks #50 at room temp. I have tried it heated and can't tell any difference. Tough Quench does need to be heated to get the speed needed for W2. And yes, clay coated blades quenched in oil will curve down and much more on the second and third quench. They curve up when quench in water.

Daniel, the second heat treat does completely erase the first. I had good ideas along these lines but didn't work out.

W2 is good stuff for those who like the hamon or just a really good cuttin blade :)
 
sunfishman said:
Good lookin hamon Wulf.

Joe, I do use Parks #50 at room temp. I have tried it heated and can't tell any difference. Tough Quench does need to be heated to get the speed needed for W2. And yes, clay coated blades quenched in oil will curve down and much more on the second and third quench. They curve up when quench in water.

Daniel, the second heat treat does completely erase the first. I had good ideas along these lines but didn't work out.

W2 is good stuff for those who like the hamon or just a really good cuttin blade :)
Click to expand...
According to the charts that I have seen, Tough Quench is a "fast" oil in the 10 second range at 150, but it slows down both at 100 and 200 by a couple of seconds. The times listed were almost identical for 100 and 200.
 
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