Didn't harden in water.

csalt09

Well-Known Member
I tried quenching a couple w2 1/8" profiled knives in water. I didn't grind the bevel yet. I'm just playing around and I usually quench in parks 50 and have been happy but just wanted to experiment. Neither knife hardened. There was a lot of the boiling type activity going on and I used my same program I use for 1/4" w2 (1460 for 20min). Could the steel have gotten to hot?
I'm going to try it in parks next time. This is the first time I used this particular bar of w2.
 
I was wrong, it did harden but I had to grind a lot of steel before the file would skate off the blade. I assume it was decarb but I usually don't have to grind that much away before the file skates.
 
I'm not trying to be combative, but I've gotta ask the question...... Why would you soak W2 for 20 mins? In most cases the long soaks that I see people saying they use is horrible for a finished knife blade. All that's necessary is long enough to get everything into "solution"......anything beyond that is detrimental to the steel/blade.

The fact that you have to grind anything off in order to reach hardened steel should be a "red flag" that you're soaking at or above the correct temp for far too long.

Personally, time and experience has taught me that only those steels that REQUIRE soak time should be..... and then only the MINIMUM necessary. That being said, W2, because of the vanadium, requires a "soak" to achieve optimal results, but we're talking MUCH less then 20 mins....more like
2-4 mins. The less soak time ONCE everything is in solution, the better.
 
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Thanks for the response Ed. I was under the impression w2 needed 8-10 minutes to soak. I used 5-10 min extra to come up to temp. That being said with 1/4" I get better results than I did with the 1/8". Maybe that is because since it is thicker it is taking more time to come up to temp therefore the soak time is shorter. Some of the decarb is from the normalizing and thermal cycles but I got much more with the thinner steel. Ill try less soak time. Thanks
 
W2 does need a soak, 20 minutes isn't all that long. The vanadium in W2 will pin grain boundaries, so as long as the temp is kept tight, and under 1500F, best 1460-1475, then you could probably soak W2 for hours without any discernible grain growth, or doing anything detrimental. The reason W2 needs the soak is because it is hyper-eutectoid (extra carbon). There are 2 ways to get that extra carbon in solution.....temp and time. To put that extra carbon in solution with temp (1500f+), then you get some unwanted problems.....RC numbers actually go DOWN, retained austenite goes UP, and larger percentage of plate marteniste instead of favorable lathe martensite. The other way to put that extra carbon in solution is time. Use 1475F, with a soak. Often 10 minutes is recommended, but thicker pieces may need longer soaks, and it should not be blowing up the aus grain.

I recently did some testing on 1.2442, which is O7, or O1 on steroids. Did a 20 minute soak at 1490F, broke the blade to check grain size, and it looked exactly like the grain of a file or drill bit. That is to say...just a gray surface with no "grain" or "texture". This alloy does not have any vanadium, but plenty o tungsten, which does the same job as vanadium.

Decarb is by FAR the biggest cluprit in "why didn't my blade harden?" threads. It can often be much deeper than anticipated. I highly recommend ATP-641, as it will stop decarb and scale dead in it's tracks. I am finding out that some alloys only need a thin wash, others like 1.2442 need a thicker layer.
 
I did a lot of testing with 1/4" w2. 1460 seems to be the best temp for my oven. 1470 will start to give me a little grain growth. I will have to break the 1/8" w2 and check my grain. I will get some ATP-641 thanks. I was under the impression that as long as the temp was proper time wouldn't make a significant difference when it is only a matter of minutes. I use a evenheat oven so I have decent control of temps.
 
There should be ZERO grain "growth" with W2 at a temp of 1470F. That's what the vanadium is in there for. Probably not any significant grain growth until 1750F+.
 
you might want to get some temperature crayons or pottery kiln cones and verify your furnace temps. a 10F degree change of temperature shouldn't effect your work, with many thermocouples that is the possible error at 1500F.
 
What kind of stock did you use? By that I mean precision ground, hot rolled, cold rolled, etc.
 
Ill have to find the broken pieces and look again, maybe it was just the way they broke. I have a 1450 tempilstik and it shows my oven reading 10 degrees low. I need a couple more to get a better range. I have w2 from Also. It looks to be precision ground.
 
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