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The Newbies Arena Are you new to knife making? Here is all the help you will need. |
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#1
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HT of Aldos W2
I would like to know how I can best HT Aldos W2 with the equipment that I have. My equipment consists of homeade propane forge, 4 gallins of canola oil in quench tank, a magnet and a 1500? temp pen which I think may be too high of a temp for W2? I have tried a few coupons and the grain size is larger than 1084 leading me to think that either my canola oil isnt fast enough or I am not soaking it long enough. When I break the coupons they are not as brittle as the 1084, they have some give to them.
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#2
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Kyle your canola is too slow and 1500 is too high. Remember it is a water quench steel, but it also tends to crack in water. 1425 to 1475 and no higher for it and you need something like Parks 50 oil. A thin viscosity oil. The book on it says to quench in brine at 70 degrees which is fine for the thick machine parts I was doing, but a lot of makers here will tell you to expect about a 50% crack ratio with knives. The 1500 is too high for certain, you can try to take it to nonmagnetic, 1413 and hold for 30 seconds and quench in brine at about 100 degrees for a start if you can't afford a fast quench oil, straight water makes a vapor barrier and will not quench as fast as brine. Temper immediately at 425 for one hour 2x should leave you around RC60.
Have you solved your forge's uneven heat problems? Also why are you messing around with W2? It is not a beginner's steel, you'd be better off with O1 than W2 Kyle, it's sweet spot is 1475, but 1500 isn't too hot for it. Here is a link to buy Tempil sticks up to 1800 and they have a 1450 stick. http://www.markingpendepot.com/tempi...ormarkers.aspx |
#3
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I think that the reason you are not getting your W2 coupons as hard (brittle) as the 1084 is that you are not cooling them quickly enough due to the wrong quenchant and/or the coupons are too thick to harden. Remember that W2 is low hardenability and any coupon between ~1/8"-1/4" just won't cool fast enough to convert to martensite or will only partially convert to martensite with the rest being pearlite.
The quenchant has nothing to do with grain size. You are getting the steel too hot for too long. A longer soak before quenching will only aggravate the problem of grain size. It will also aggravate the problem of retained austenite. W2, as well as O-1 are hypereuticoid steels the aim in austenizing these steels is to only put part of the available carbon into solution and that's difficult to do with a gas forge. You need to restrict yourself to friendlier alloys such as 5160, 1075, 1080, 1084, or 80CrV2. Doug __________________ If you're not making mistakes then you're not trying hard enough |
#4
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There are a few reasons why W2 is not an easy steel to heat treat, and the posts above mine hits on many of them. I'll try to enumerate....
1. It is hypereutectoid. This means extra carbon. Requires that you have the ability to hold an exact temperature for a soak period. ie: 1475F (or 1450 or 1460...whatever your testing results give maximum HRC) for 10 minutes. This is all but impossible to do without some sort of controlled heat, like a kiln or PID controlled forge. If you simply heat it to around 1500 and quench, you'll have a 1084 blade, not a W2 blade, sort of, not exactly but sort of. 2. It is very very shallow hardening, much more so than 1095 even. This means that your quench must be very fast in order to harden it. Canola at 130F is considered a semi fast oil, but not quite fast enough for the performance W2 can bring to the table, especially in cross sections 1/8" and over. However, you can do an interrupted quench. That is to say, quench in water or preferably brine for 2 seconds, then finish off in the 130?F canola. If you will be working with W2 in the future, do yourself one of the biggest favors you can, and bite the bullet and purchase 5 gallons of Parks 50 oil from Maxim in FT Worth TX, or DT-48 oil. 3. The W2 from Aldo is coarse spheroidized. This means that you will need to normalize and then cycle the steel, even if only doing stock removal. That means, briefly without explaining in detail what/why: 1650F 20 minute soak, air cool. Now it's normalized. 1550F short soak air cool. 1450F short soak air cool. 1375f short soak air cool. Then harden. If you do not do this procedure with Aldo's W2 and Aldo's 52100, you likely will not reach max HRC with just a hardening procedure. You may do OK without this routine...I have heard of people successfully hardening Aldo's W2 without normalizing/cycling, but on the other hand I have heard some reports of this W2 not hardening unless it was normalized at forging temps (1900F). There are issues with some of the W2, as mentioned. I won't get into all that because they are hit/miss, not everyone has had the problems. I have not had any issues, the batch I got was OK. Note, all thermal cycles including hardening should be done with some sort of anti decarb protection, like ATP 641. If none is used, then make sure you grind/sand thru the resulting decarb layer before hardness testing. The decarb layer will trick you into thinking it didn't harden, when it may have. |
#5
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I only have the W2 because I ordered a section of it when I got my 1084 per a recommendation on here. I have read about the temps an have been getting it as near 1450 as I am able to. I did not know it was coarse spheroidized which explains the large grains. I think the canola oil is the reason its not hardening. When I break the coupon it isnt brittle but bends a tiny bit before snapping. I just thought it would be fun to play with a different steel since I had it laying around.
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#6
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I can understand experimenting Kyle. I also do not mess with W2 for all the reasons in the posts above and I do not have an electric oven to do it right, but I would use brine at 100 degrees and take my chances. That link I gave you above will also make custom Tempilstiks for 1475 if you want and they run about $12 so not too high.
Now did you get your uneven heat in your forge fixed? If you haven't you will have to stick to the higher heat steels, there's no getting around it and for W2 1500 is too hot. My brother and I had his forge fixed to hold pretty close to the temp we wanted by using propane and compressed air. Just an idea if you have a small compressor as it doesn't take a large air flow to get where you want. |
#7
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The heat in it is still uneven. I have to move the blade a lot and go really slowly to get the steel to heat evenly. I do have a small compressor and a large one as well. I may just set the w2 aside for now though.
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#8
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The course sphodization of carbides is different than course grain, though neither is desirable. The course spheroid carbides come from that way the steel was heat treated at the foundry and is corrected by the method sited above. Grain growth has to do with the basic iron matrix. At high temperature over time, with temperature being the most critical, the small iron crystals can combine into large iron crystals. This allows for a longer interface between the crystals that can shear under stress. The broader crystals also make it difficult to get a fine edge on the blade.
I once experimented with 52100 so I know the attraction of "super steels". I made two test blades, each by a different heat treating method and I think that they came out well. However, I came to the conclusion that I probably wasn't getting the most out of the blades that I could have and that it would be harder to get consistent results from the steel without a regulated high temperature oven or a high temperature salt pot. It just reinforced my belief that you need to stick with an alloy that is compatible with your equipment. Doug __________________ If you're not making mistakes then you're not trying hard enough |
#9
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That sounds like a good idea Kyle as I didn't know that Aldo's W2 was coarse spheroidized either and there is no point in making a knife with it if you cannot properly normalize it to HT it correctly like SamStuart explained. BTW Kyle did you get Ray's video on how to build a forge? I understand your reluctance on building a new one, but you need a better forge without a doubt.
If your burner is configured wrong you will have to change it and how big is the I.D. of your forge? If it is too big for your burner and gas/air flow you will get uneven heat. At what angle is your burner pointed? Before experimenting with new knife steels I would be either fixing or making a new forge. You need a consistent forge Kyle and having to constantly move the blade at high temps is restricting what you can do. |
#10
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my plans as of now are to get a HT oven in the future and stick with 1084 for now. the ID of my forge is definitely too large for my current burner. the burner is at a fairly good angle now and swirls well but theres too much area inside the forge to get even heat. I am going to do mainly stainless I believe once I get my grinding a lot better. I will send them out for HT when I have enough to make it worth it. I am working on a little neck knife that is a cleaver right now and actually did half decent grinding it (atleast for me). I will start a new thread with a few pics of it when I am done.
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#11
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Just wanted to give the group a heads up. I was concerned after reading Aldo's W2 was being shipped from the plant coarse spheroidized so I emailed Aldo to see if this was true.
I was hoping to get an email from someone in his sales department but I didn't. I did however just get off the phone with Aldo who personally called me (talk about customer service). We had about a 10 minute conversation during which he assured me that the W2 is not coarse spheroidized and is ready to be worked with on arrival. He did say that he doesn't like to HT carbon steels in an oven due to the oxygen rich environment. So now I am going to buy some anti scale powder. I know about brownells anti scaling compound, but I remember reading a thread a while back about a different anti scaling compound that was getting good results too. If anyone remembers what the other one is please let me know. |
#12
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An oven doesn't have to have an oxygen rich environment, you can flood it with argon. All my blades, carbon and stainless, were done that way ...
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#13
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Quote:
Those of us who work with Aldo's German steels have figured out that if you don't want to waste time and cuss the steel because it didn't harden properly normalize and thermal cycle it. That means his 1084, W2, and 52100. I konw the 80CrV2 and 1095 are good to go. And of course O1, A2, and the CPM steels are ready to go. As far as I know his 52100 is still received coarse spheroidized, and assumed his W2 is like it has always been. The 52100 from Chuck at Alpha Knife Supply is fine spheroidized. Do a search about Aldo's W2 on Bladeforums and read all the talk about it, if you care to. Last edited by samuraistuart; 01-06-2017 at 11:14 AM. |
#14
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I have an evenheat kiln, to the best of my knowledge they dont make an argon gas injection system for that brand. I've also heard that the gas will shorten the life of the coils. I guess for now ill try the cheaper option and see if it works for me.
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#15
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Adding argon to any oven is fairly cheap and easy to do. All you need is a regulator and eBay usually has lots of them. Argon could shorten the life of the heating coils unless you break them in first and that too is easy to do. Heck, considering the convenience of not having to use foil or anti-scaling compounds I personally wouldn't care if it did shorten the life of my elements a little.
But, argon does not prevent all scaling and therefore I only recommend it to those willing to do their grinding post heat treat. I prefer post HT grinding because it means I can get a profiled blade into HT very quickly and not have to waste further time on it if for any reason the HT fails (blade warps or cracks or fails to harden properly). Post HT grinding seriously reduces the chance your blade will warp (often caused by uneven grinding). Another benefit is that you will be certain of grinding off any decarbed steel on your way to the final blade shape. Like argon, post HT grinding isn't for everybody but if you can do it , it can streamline and speed up your process to a finished knife ... |
Tags |
1084, 5160, back, beginner, blade, book, buy, carbon, degrees, forge, forging, harden, heat, heat treat, hot, knife, knives, makers, o-1, pen, post, problem, steel, temper, water |
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