In hind sight I should have started with this question and I apologize for not doing so. I am making some hunting knives out of W2. I picked this steel because it is supposed to perform well and I would like to try a few hamons. What would be a good Rc to have this steel at for a hunting type of knife (with good edge retention) and how do I achieve it with a brine quench? I have made a few with them at 1460F for 10 minutes, a brine quench (1 pound salt per gallon of water) with the brine at approx 70F and 2 one hour tempers @ 425F. Thanks in advance.
W2 Rc question
- Thread starter KDX
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taylormadeknives
Well-Known Member
I wouldn't know much about the brine. I know it does perform well in the field. I recently finished one up for a guy using it. I quenched it in Parks 50 and used Rutlands furnace cement. It had a very nice hamon. There are lots of variables, but it's not hard. The brine is just too risky for me. The Parks is very fast oil without the risk of cracking the blade. My customer had no complaints on the performance of the knife. He took it to Texas and used it on 3 whitetail and said it was still shaving sharp at the end of the day.
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jmforge
Well-Known Member
Somewhere north of 60Rc. Some very knowlegable folks have argued that you are leaving too much on the table by leaving W2 "soft" Remember that in all but the thinnest places, the core up by the spine may be a bit softer, giving you that "unintended toughness" along with your "accidental hamon" :3: If I were in your shoes, which I was a number of years, I would buy some Parks 50 or the equivalent Houghton very fast oil. You don't have to preheat Parks 50 unless is it cooler than 70F.
Doug Lester
Well-Known Member
First of all, do you have a method of testing the HRc of your blades or are you just looking hardness temperature charts and hoping that you are achieving a given hardness? It's a little pointless to tell you to aim at a given HRc if you can't measure it. Most of us don't have a hardness tester and the best thing is to go by actual blade performance to see if they have a heat treating regimen that produces what they want. Granted, with W2 I would try to would try to get a harder blade for something just intended to field dress a skin game with.
If you do have or have access to a hardness tester be aware that you might not be able to accurately measure the hardness of a W2 blade. This is due to the fact that you need parallel surfaces to measure and that will mean measuring at the ricasso instead of the bevels. The ricasso may be too thick to harden if you maintain nice fine grain.
Doug
If you do have or have access to a hardness tester be aware that you might not be able to accurately measure the hardness of a W2 blade. This is due to the fact that you need parallel surfaces to measure and that will mean measuring at the ricasso instead of the bevels. The ricasso may be too thick to harden if you maintain nice fine grain.
Doug
jmforge
Well-Known Member
if you fully quench W2 with no clay, the surface of the ricasso should still be as hard as woodpecker lips coming out of the quench even if the interior isn't. That is actually how the stuff was designed to work in typical thicker tooling applications from what I understand. The beauty of that property in a knife application is that you can get a similar benefit to that of the high carbon outer "skin" forged around the low carbon interior using the "hotdog and bun technique" for welding technique that you see in simpler construction traditional Japanese swords, but using a monosteel.
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Knifemaker.ca
Dealer - Purveyor
The next time some woodpecker flies into our atrium windows and stuns itself, I'm heading straight for the shop with it. Inquiring minds need to know.
Doug Lester
Well-Known Member
Actually, when you start dealing with thin sections of steel, let's say about 1/4" or thinner, the outside and the inside of the steel cools at very nearly the same rate. ( ref: Vanderhoeen, Steel Metallurgy for the Non-Metallurgist pg 88). What that boils down to is that if the steel won't cool quickly enough to miss the nose of the cooling curve because it's too thick then it will only partially harden or form all pearletic steel. You won't get a jacket of hardened steel around a pearlite core with something as thin as a blade. If you did get t hat jacket of martensetic steel around a pearletic core then you would not be able to get those "automatic" hammons that perplex people when their hammons don't go up to where they clayed the blade.
Doug
Doug
samuraistuart
Well-Known Member
Reading your post Mr Lester, I am left scratching my head. My knowledge is no where near yours, so please don't misunderstand, I am just trying to understand this. Basically you are saying that W2 cannot be RC'd accurately on the ricasso because the ricasso is thicker than the blade? If that is the case, how are any W2 blades tested? You can't test them on the blade itself of a full flat ground knife anyway...unless you are able to mount it very well to where the blade surface is squared up to the diamond penetrator. I see how you would easily get a reading off of the flats of a saber grind. Otherwise...it is the ricasso we are left to test with...is it not?
If I understand what you're saying...the ricasso being thicker than the blade....you'll end up with pearlite there. I sure would not have guessed that. The way I thought it worked with W2 was something like this....a 1/8" coupon in a brine quench might fully harden all the way through and be 66. A 1/4" coupon may or may not fully harden, but the skin to a certain depth would be 66, then maybe 65 as you get deeper, then 64 deeper still. A 1" coupon would still get 66 on the surface, but because of how thick it is (mass) the center may not get above 40 or whatever. Is that wrong?
I get the hamon thing....makes me wonder if I know anything at all!!!!!
If I understand what you're saying...the ricasso being thicker than the blade....you'll end up with pearlite there. I sure would not have guessed that. The way I thought it worked with W2 was something like this....a 1/8" coupon in a brine quench might fully harden all the way through and be 66. A 1/4" coupon may or may not fully harden, but the skin to a certain depth would be 66, then maybe 65 as you get deeper, then 64 deeper still. A 1" coupon would still get 66 on the surface, but because of how thick it is (mass) the center may not get above 40 or whatever. Is that wrong?
I get the hamon thing....makes me wonder if I know anything at all!!!!!
Doug Lester
Well-Known Member
All I can say is what Verhoeven said in his book. Thickness is also an issue to you may well get a 1/8" coupon to harden all the way through, actually I would sort of expect it, and a 1/4" coupon will not. Here again we have those annoying (or not) "auto-hammons" where the blade just doesn't seem to harden over around 1/8" thick. You can etch a blade like that and at the junction of the martensetic and pearletic steel the line will show up between the two steel phases. The ricasso will take on the etching characteristics of pearlite the same as the spine. Another thing that comes into the mix is grain size. Larger grain promotes hardening. If the grain is large enough then the 1/4" coupon will form martensite with a loss of strength due to the grain size.
As far as how one would get a measurement of hardness at 1/8" or thinner with fine grain, you would make a coupon of that thickness and take it through the hardening and tempering process that is being tested and measuring that. It's not just the W series of tool steels that act like that. Other shallow hardening steels like 1095 or 1075 will do it too. This is where the low alloy steels like the 1080 that is out on the market which is actually 80CrV2 or 1084 which is really 1084 plus a little chromium come in handy. They will harden past 1/4" thickness. 5160 steel would have the same relationship to 1060.
Doug
As far as how one would get a measurement of hardness at 1/8" or thinner with fine grain, you would make a coupon of that thickness and take it through the hardening and tempering process that is being tested and measuring that. It's not just the W series of tool steels that act like that. Other shallow hardening steels like 1095 or 1075 will do it too. This is where the low alloy steels like the 1080 that is out on the market which is actually 80CrV2 or 1084 which is really 1084 plus a little chromium come in handy. They will harden past 1/4" thickness. 5160 steel would have the same relationship to 1060.
Doug
jmforge
Well-Known Member
From what I have seen, most of the 1080 and 1084 out there is also going to have up to twice as much manganese as say W2 or garden variety 1095. Still shallow hardening, but not quite so shallow.
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Warren Krywko
Well-Known Member
In a round section, you will get a layer of martensite around a softer core. With a wedge, you get differential hardening.
samuraistuart
Well-Known Member
Thanks Doug and Warren. I keep forgetting about coupons....thinking you're left testing your knife. Not the case!
If i don't remember wrong if the surface is hardened, so it is into the core at that thickness level.
The hamon line develops almost perpendicular from one side to the other, it doesn't "fold" around the core significantly.
The mass of the steel doesn't allow for the surface to cool too much quick then the core...in the same way you can boil water into a plastic bottle on a barbeque without burning the plastic
The hamon line develops almost perpendicular from one side to the other, it doesn't "fold" around the core significantly.
The mass of the steel doesn't allow for the surface to cool too much quick then the core...in the same way you can boil water into a plastic bottle on a barbeque without burning the plastic