D2 and Rusting

galadduin

galadduin

Joined
Dec 25, 2004
Messages
1,363
I made a fruit knife from D2 last week. After froging, HT, I ground it and sharpened. I was not so happy with the edge holding after making handle and testing it. The profile and the handle turned out real good (I used a textured corian and mosaic pins) but the performance of the blade was not so good; dulls pretty easy. My sister wanted this knife but I didnt want to send it as it was not perfect.

Also the blade rusts very quickly. I rub the blade with 2000 grit to remove rust, after a couple hours it has rust spots all over the surface and a strong rust smell.

I couldnt figured where I went wrong. I guess it is forging or HT, but I'm not sure.
 
Several possibilities here.Are you sure it was D2? First,you could have over forged it down to low carbon steel.Second you could have decarbed it so bad in HT that it is low carbon now on the surface.If this is what you put in your molten borax it could be eaten by the borax down into the grain,and is now leaching boric acid. Your description of the edge holding problems implies that if it was D2 to start with,it isn't D2 any more,or it is badly mis-heat treated.
 
I think youre darn right, This is the one I covered with borax. Also it was a recycled piece from a warped blade. It was forged and after it was recycled it was also forged to shape. Damn, I tried too much for this piece of steel, now I have a low-carbon, huh :( . No matter, I quit to use D2 anymore, that was the last try.
 
Don't give up on D2. When you figure how to forge it right it makes a great blade.

Larry
 
Why not just grind a blade out of D2. It's done all the time, and it makes excellent blades. It doesn't really gain anything by forging anyway.:eek: :confused:

To me, it's like forging 440C, ATS34, etc. Sure, it can be done, but to what purpose. After all the time and trouble, you still have 440C, ATS34, etc., with no gains, and probably the worse for wear in the bargain, as the D2 above shows.
 
I have always wondered why people forge D2, also. When it comes to performance, I have no doubt that some can forge and heat treat a D2 blade that will perform as well as any, however the odds are against it being done every time. It can decarb with repeated heat cycles, heat treating without a furnace to allow for soaking before ramping up to austenizing temp would not be optimum for the very best heat treat.
 
Nowicki said:
Don't give up on D2. When you figure how to forge it right it makes a great blade.

Larry
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Thanks Larry, I will forge some other time as there is almost 100 pounds D2 sitting in my stock. Now I plan to make some damascus ;) :cool: ...
 
Mike Hull said:
Why not just grind a blade out of D2. It's done all the time, and it makes excellent blades. It doesn't really gain anything by forging anyway.:eek: :confused:

To me, it's like forging 440C, ATS34, etc. Sure, it can be done, but to what purpose. After all the time and trouble, you still have 440C, ATS34, etc., with no gains, and probably the worse for wear in the bargain, as the D2 above shows.
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I am not used to the stock removal. The time spent by the grinder makes me sick. Forging a piece to the shape requires much less time. The shape after 10 minute forging requires 1 hour of grinding. Lets add 5 min of heating the forge. I cut to the shape with hardie, shape the bevel and ricasso. That takes only 20 - 30 min of forging and after that 15 min grinding with 60 grit and the bevel and profile is acquired. The most time is spent to anealing and making handle. I dont know how you finish a blade by stock removal but I tried and it just bores me. Also I am not restricted by the size of the stock I have and in this country I can find mostly round stock.. I will head to damascus and swords as I am a forger type of person ;) .
 
My experience with D-2 is that it is one of the tuffest steels to forge expecially if your doing it by hand. By what you just wrote it sure doesn't sound like D-2 to me. How are you heat treating it?
 
D2 is SUPER in the edge holding dept

not so good in the corrosion resisitance, in fact, it rusts so readily here in Hi that I stopped using it many many years ago for that very reason.
 
Here in New Mexico, we have a semi-arid climate which I think is much like yours in Turkey. D2 in the annealed state rusts readily, but is very rust resistant after heat treat. After heat treat, it stays bright very well. From your description, it sounds like you are not getting a thorough hardening cycle.

D2 is classed as an air hardening steel and as such, needs to be forged only above the critical temperature,>950°C.

All of the manufacturers of D2 that I am familiar with call for a 30 minute minimum soak at hardening temperatures for carbide solution. If you short this time, you will lose some of the effectiveness of your heat treat. High alloy steels, especially with significant Vanadium content require long soak times. The Vanadium works to control grain size, which does not happen in simple Carbon steels.

Remember the 1.5% Carbon here is wt%, when you look at Mol%, I believe it will be around 3-4%, I haven't attempted to dredge up my chemistry skills to fugure it out exactly.

You might look into getting a used pottery kiln to adapt for heat treating. If you use a good pyrometer and pay attention, you do not need digital controls. You do need to control the atmospheric interaction during the heat treat.
 
What do you prefer Tom? I too have had a customer that needs a rust friendly knief.
 
Nowicki said:
Don't give up on D2. When you figure how to forge it right it makes a great blade.

Larry
Click to expand...
I'll second that for Larry. I used one of his forged D2 scalpels skinning a couple of deer this past fall and had no trouble in the edge holding and rusting department. I've made about fifty knives out of D2 by way of stock removal and have had no complaints of either problem. The edge holding was outstanding with the D2 that had also been cryo treated.
Scott
 
Raymond Richard said:
My experience with D-2 is that it is one of the tuffest steels to forge expecially if your doing it by hand. By what you just wrote it sure doesn't sound like D-2 to me. How are you heat treating it?
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First I take an annealed D2 bar ofcourse. If it is not annealed I cant forge it easily.

I forge it just under the light orange color means for me just on the critical temp. I have a precision equipment for deciding the critical: a magnet :D .
When it doesnt stick, I take it out and hammer. When I see RED I know I have to stop, dunk it to the forge again. It goes on like this, after the profile is Ok then I work on Dark orange -a bit below critical this means- shaping bevels. As the bevel progresses I lower the working temp. I stop when it falls to Red. This way I manage to aus-forge the bevel parts as Mr. Hirosoulas says. As the forging is finished I heat the blade to critical and shot down the forge. My forge floor is filled with 2 inch thick cat-litter, I burry the blade and put on top the orange glowing fire-bricks. Then I cover every opening with ceramic-fiber (kaowool): the burner hole and doors. The blade cools down to dark red in 8-10 hours. After 12 hours I pick the blade, it is around 300 - 400 C. Let it cool and test it with a file if it is soft. Then I grind just to remove the hammer marks and scale. Then clay and fire-clay mix dilluted and very thin layer covers the blade. Let clay harden. Then the forge is heated, the blade is pre-heated to red with a torch veeeery sloooow. Mostly it takes 10 minutes to reach to red (around 650-750 C) Then to the forge, let it soak just above critical about 25-30 min. Then quenched with the air blown on the blade. I learned that if it is blown to the side of the blade it is more likely to warp, so air is blown from the spline. When it is barely holdable I temper 1 hour and 3 cycles at the owen. Thats how I make D2 knives, Ok most of the time I fail but I am novice you know, I have to fail to learn.
If the process is wrong , tell me guys, please correct me, I desperately in need of correction :( :confused: :D :cool: .....

Best wishes
Emre KIPMEN
 
You can find info on heat treating D2 at www.crucibleservice.com The Hardening temperature is 1825-1875 F [ ~1000 C] - no wonder it's not working !! Please remember that the more complex the steel the more complex and critical is the heat treatment !!!
 
mete said:
You can find info on heat treating D2 at www.crucibleservice.com The Hardening temperature is 1825-1875 F [ ~1000 C] - no wonder it's not working !! Please remember that the more complex the steel the more complex and critical is the heat treatment !!!
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:confused: :confused:
Mr mete,
where do I go wrong. I soak it at slightly above critical, the critical is around 950 right. That means I soak it around 1000 - 1050. why "no wonder" you say. If it is wrong what should I do?
 
This is no answer to why your blade is as soft as you indicate however, I would soak the blade closer to about 17 minutes (depending on thicknes) and for forced air cooling I would prefer the air flow into edge or into point - not into spine.

RL
 
You preheated to 650-750 C. Normal forging temperature is 1850-2000 F. Hardening temperature is 1825-1875 F.You say 'heated just above critical' except that 1850F is more than' just above critical'. To obtain proper hardness and corrosion resistance the alloying elements must be thoroughly dissolved in the austenite .That can only be done at the higher temperatures of 1850F. You must be able to determine proper temperatures. D2 is quite corrosion resistant and holds an edge very well if heat treated properly. Try again !
 
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