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Author Topic: D2 Experiment Failure, implecations for a stock-reduction HEPK??  (Read 2144 times)
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Harold Locke
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« on: November 27, 2011, 03:50:30 AM »

D2 Experiment Failure

As others expected my attempt using D2 steel has resulted in failure. As all good failures should do, this one is no exception. As I was doing the testing on my sacrificial blade for the batch of 10 D2 blades. The point test with over 10 good firm jabs into my aluminum test plate no deformation - Success! The edge flex test after sharpening took 11 firm pushes across sharpening steel, no chipping or deformation - Success! The cutting test - failure, have sharpened the edge over 10 times already, and after one or two cuts on rope, wood, paper the edge disintergrates. This is exactly what Ed told me a couple of weeks ago would happen. The eperiment has some good examples as to why it failed and numerous things to think about for future experiments.

My original concept of this experiment was to see if there might be a golden - mean of some sort that could be applied to steals in general. So in this case my standard was based on Ed Fowler's work with 52100 steel. Having been to his seminar on forging I started with the Tempertures and Times that were being used at that time on the steels Ed was using at that time.

I was compareing the temps and times that Ed was using with that of the suggested times of the big steel plants. I used the spec sheets from Crucible Steel, I made precentages on the differences bettween Ed and Crucible for 52100 steel. Took those precentages and and applied them to D2 steel temps and times as recomended by Crucible.

Lesson 1:  The nature of the alloying of steels prevents any generalized precentages being applied to temps and time.

The test was completed on Nov. 27, 2011, started on or around the June of 2010. The test was done from a scrap of D2 steel of which 10 knives were cut out.

Lesson 2: When you are experimenting only prepare what you need for completing it. Thought that that this experiment might work. Put alot of time and money with belts, electricity and oxy/acet into all 10 blades and didn't need to.

The blades were annealed with 3 stress releiving cylces with at least 24 hrs in the deep freeze between each annealing. They were then profiled to their basic pattern and each was ground  to its preheat treatment form. At this point 3 hardenings were done useing the Torch and Type A quenchent to apply a differential style treatment, with 24 hr deep freezes bettween. Three (3) Tempering cycles were finally done with the same 24 hr deep freezen bettween temperings.

At this point all I have is questions??????. . . .

Q 1:  Should non hand forged steel have multiple heat cycles, was the edge failure because of extreme grain growth?

My biggest wonder, when starting this test Larrin was making a statement that in his experience his blades always seem to flex the same amount of times when heat treated as they did in their annealed state. My first sacrificial blade was done after the first 3 annealing cyles of heat and freezeing. The annealed blade made 8, 90 degree bends or 4, 180 degree bends.

Q 2: Should I do the last test of bending to destruction? The etching of this blade showed that my hardening went high, even with the level of quench to the bottom third to half of the blade.

Q3: Should air hardened steels even be attempted in an oil quench. The factory spec sheet said it was possible to do a successful oil quench, if so how.

Stopping my report here, don't even know if anyone will be interested. I don't have the answers to my questions, but am thinking about them. Answers and comments are welcome. Also, took pics, if anyone interested.

Harold Locke





















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Ankerson
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« Reply #1 on: November 27, 2011, 07:01:27 AM »

Interesting that you didn't try that with 52100 instead of D2 if you wanted to make a direct comparison as 52100 doesn't have to be forged.

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Ed Fowler
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« Reply #2 on: November 27, 2011, 10:12:42 AM »

Harold: That was a lot of work: Thanks for sharing your quest with us! We don't know if we don't try.

I never could develop the blade I wanted out of D-2, quit using immediately after my time with Bill Moran. Joe Szilaski forges it and makes it work, he has quite a system worked out and I have one of his blades, it cuts well but I have not tried any destructive testing on it as it is a completed folder and was a prototype, he has only made one other one.

When it comes to air hardening steels, my experience is limited to an experiment Rex did with a batch, they increased tensile strength by 235 psi using multiple air hardening quenches. He noted that the first trip down through critical took 16 seconds, the second quench took around 12 seconds and the third quench took less than 6 seconds. The time it took going up through critical also decreased with each cycle. When it works there are many indicators that we can watch for during the development.

Years ago I forged two blades out of 440C and use differential multiple quench in Texaco type A, the test blade cut about as well as you can expect for 440-C, the blade was tough and did multiple 180 degree flexes. I gave the blades to Wayne Goddard who was going to test for corrosion resistance, but he had a show coming up and simply put both of our names on it and sold it to a man who fell in love with her.
The blades came out or a 2 inch ball bearing so they had a rate of reduction in the high 90's which would make a difference between stock removal blades of the same steel.


 
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ChrisAnders
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« Reply #3 on: August 26, 2014, 03:14:17 AM »

Is Harold still active?  Is there any interest in pursuing this further?  This was one of the threads/discussions that made me want to join here.
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Daniel Rohde (D-Vision)
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« Reply #4 on: August 26, 2014, 05:53:56 AM »

I haven't seen him around in a while but he mite be.I hadn't read this post but it's really interesting and it's fine to post on old thread around here.
Daniel

side question: can you air harden a stainless steel blade and then give it a soft spine draw to get a differential hardened blade?
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Ed Fowler
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« Reply #5 on: August 26, 2014, 07:23:01 AM »

Harold is one of the good guys, has been taking care of his mother and I have not talked to him for a long time.  That was one great experiment he did. I miss his contributions.
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