How brittle is D2?

[OldPhysics]

And from the DiamondBlades site:

"How Friction Forged Blades Began: The Idea
In 2003, two quail hunters, Hobie Smith of Smith International, Inc. and Charles Allen, Knives of Alaska's President, were teamed up at the Grand National Quail Convention, an annual fund raising event in Enid, Oklahoma for quail conservation and research. As fellow bird hunters will do through the course of the day, conversation revolved around quail hunting and management, bird dogs, the Grand National, and eventually what each did business-wise. Hobie's Smith International has two operating units in Provo, Utah-MegaDiamond and MegaStir-both concerned with manufacturing synthetic diamond and other "ultra-hard" materials for oil field drilling bits and other specialty tools. Knives of Alaska manufactures high quality outdoorsmen's knives.

The discussions eventually led to the challenge "LET'S TEAM OUR COMPANIES UP AND BUILD THE MOST TECHNOLOGICALLY ADVANCED BLADE IN THE WORLD."

Thus it was at the Grand National that a four-year research process began. Teaming mechanical and electrical engineers, metallurgists and materials PhD's from Brigham Young University, and manufacturing experts from MegaStir, MegaDiamond, and Knives of Alaska, eventually culminated with meeting the challenge. Their research yielded newly issued U.S. Patents concerning technological advancements in knife blades that are "a technological leap ahead" of any other knife in the world-FRICTION FORGED® SUPER BLADES-and resulted in the formation of the new American knife manufacturing company, DIAMONDBLADE, LLC, that builds the Friction Forged® blades."

For the skeptics (most of us, I assume), there are some very fine and very careful scientists at BYU.

For those who prefer a little research of their own:

http://www.diamondbladeknives.com/index.aspx

 

[OldPhysics]

My memory was 'stirred' by an actual metallurgist, D. Scott McKenzie, on SwordForums. You can find out more about the process used to friction forge at this link:

http://www.azom.com/details.asp?ArticleID=1170

It was originally called "friction stir welding." From azom:

Friction Stir Welding
Friction stir welding also produces a plasticised region of material, but in a different manner. A non-consumable rotating tool is pushed into the materials to be welded and then the central pin, or probe, followed by the shoulder, is brought into contact with the two parts to be joined, figure 2. The rotation of the tool heats up and plasticises the materials it is in contact with and, as the tool moves along the joint line, material from the front of the tool is swept around this plasticised annulus to the rear, so eliminating the interface.



Advantages of Friction Stir Welding
The process was patented in December 1991 and the first applications have been in aluminium fabrications. The weld quality is excellent, with none of the porosity that can arise in fusion welding, and the mechanical properties are at least as good as the best achievable by fusion welding. The process is environmentally friendly, because no fumes or spatter are generated, and there is no arc glare or reflected laser beams with which to contend.

Another major advantage is that, by avoiding the creation of a molten pool which shrinks significantly on resolidification, the distortion after welding and the residual stresses are low. With regard to joint fit up, the process can accommodate a gap of up to 10% of the material thickness without impairing the quality of the resulting weld. As far as the rate of processing is concerned, for materials of 2mm thickness welding speeds of up to 2m.min-1 can be achieved, and for 5mm thickness up to 0.75m.min-1. Recent tool developments are confidently expected to improve on these figures.

Materials Suitability
Friction stir welding has been used to weld all wrought aluminium alloys, across the 2xxx, 5xxx, 6xxx and 7xxx series of alloys, some of which are bordering on being classed as virtually unweldable by fusion welding techniques. The process can also weld dissimilar aluminium alloys, whereas fusion welding may result in the alloying elements from the different alloys interacting to form deleterious intermetallics through precipitation during solidification from the molten weld pool.

Friction stir welding can also make hybrid components by joining dissimilar materials such as aluminium and magnesium alloys. The thicknesses of 6082-T6 that have so far been weld have ranged from 1.2mm to 50mm in a single pass, to more than 75mm when welding from both sides. Welds have also been made in pressure die cast aluminium material without any problems from pockets of entrapped high pressure gas, which would violently disrupt a molten weld pool encountering them.

Applications
The original application for friction stir welding was the welding of long lengths of material in the aerospace, shipbuilding and railway industries. Examples include large fuel tanks and other containers for space launch vehicles, cargo decks for high-speed ferries, and roofs for railway carriages.

 

[thombrogan]

Dr. MacKenzie is the man! It takes a Brainiac from Smartron V to walk us mortals through the heat-treatment of custom alloys and D. Scott is that brainiac.

 

[tnelson]

Okay, after reading 90% of this thread, and also having recieved and read the latest 2 issues of Blade Magazine... I hafta ask: Wayne Goddard, and Knives of Alaska, are now on about a new process for creating a "super" D2... Friction Forged D2.
In reading the articles, it's my understanding that through inducing localized intense pressure and creating intense frictionally induced heat, a process of "stirring" the steel breaks the crystalline structure down into even finer crystals than is possible either thru the manufacturing process or the traditional forging process...

Anyone on here familiar with this "new" process? And has anyone any real world experience with the resultant blade?

Thanks in advance!

Joeshredd,

We have described this in a couple of the other threads so I will post these below. One of these posts has some articles attached that you can download.

Friction Forged Baldes : CATRA Tests http://www.bladeforums.com/forums/showthread.php?t=476782

Edge Retention Testing

Under the rotation (about 300 RPM) and pressure (about 10,000 lbs) of the tool, the FF process produces a localized region of high deformation (strain). This deformation occurs at elevated temperatures in the range of 900-1000C. The high level of strain at these temperatures generates dynamic recrystallization (repeated subdivision of the original grains as a result of continuous deformation at elevated temperature) which reduces the FF processed grain sizes to <1 micron. We have measure grain size from 500-700 nanometers.

Hope that helps. if not, send me an email and I will forward you some information.

I would certainly like to run an X-ray diffractometry and tomography test on this material. I'll bet the ordering and crystalline dimensions will turn out to be quite interesting. It would also be very interesting to see how much residual micro-stress remains after the heat treat...

But that's all just the naive geek in me!

OldPhysics,

We are presently performing TEM, SEM, nano indentation, and microtensile testing on the FF D2, D2 and S30V for comparison. I hope to have some results by the first of the year. We plan to publish these results in one of those Geek Fodder journal. If you want, send me an email in January and I will forward some of the results pre-publication for you to peruse.

Tracy

 

[Jeff Clark]

I would guess that the edge recrystallization is done on a knife blank that includes the full blade outline because you want the hardened zone to track where the edge will be. My question is, "how wide is the hardened zone--how much blade would you need to hone through before you run out of the good stuff?" With the low wear rate of the steel this is probably not much of an issue, but I am curious.

 

[OldPhysics]

OldPhysics,

We are presently performing TEM, SEM, nano indentation, and microtensile testing on the FF D2, D2 and S30V for comparison. I hope to have some results by the first of the year. We plan to publish these results in one of those Geek Fodder journal. If you want, send me an email in January and I will forward some of the results pre-publication for you to peruse.

Tracy

I'd love to read that! I'll do just that ...

Glad to hear someone else is still using that old stand-by, the electron microscope. Very appropriate in this situation. Most of the youngsters have been blinded by that 'new kid on the block,' the atomic force microscope.

 

[hardheart]

that was discussed a bit in the older threads, esp. since I am no fan of diff. hardening for anything but a pretty hamon. I think 30% of the width was mentioned as a rough estimate. The spine is hardened somewhere in the 40s, IIRC.

 

[tnelson]

I would guess that the edge recrystallization is done on a knife blank that includes the full blade outline because you want the hardened zone to track where the edge will be. My question is, "how wide is the hardened zone--how much blade would you need to hone through before you run out of the good stuff?" With the low wear rate of the steel this is probably not much of an issue, but I am curious.

Jeff,

The width of the blade that is hardened is >0.150".

I'd love to read that! I'll do just that ...

Glad to hear someone else is still using that old stand-by, the electron microscope. Very appropriate in this situation. Most of the youngsters have been blinded by that 'new kid on the block,' the atomic force microscope.

OldPhysics,

I agree with you: AFM sure seems to be the new fad for the youngsters, but it sure doesn't get to what I consider the essential information: the details of the microstructure.

Keep in touch and I'll send you that information.

Tracy

 

[joeshredd]

Joeshredd,

We have described this in a couple of the other threads so I will post these below. One of these posts has some articles attached that you can download.

Friction Forged Baldes : CATRA Tests http://www.bladeforums.com/forums/showthread.php?t=476782

Edge Retention Testing

Under the rotation (about 300 RPM) and pressure (about 10,000 lbs) of the tool, the FF process produces a localized region of high deformation (strain). This deformation occurs at elevated temperatures in the range of 900-1000C. The high level of strain at these temperatures generates dynamic recrystallization (repeated subdivision of the original grains as a result of continuous deformation at elevated temperature) which reduces the FF processed grain sizes to <1 micron. We have measure grain size from 500-700 nanometers.

Hope that helps. if not, send me an email and I will forward you some information.

Thanks for the info, Tracy! :thumbup:

I guess my only other question (please excuse me if this was addressed in the other threads, as I'm about to read them,) but how does FF affect D2 with respect to impact stresses? Specifically, chopping? I see that some have found it to be adequate to cut bone in the butchering process, but suppose I only have a 5" FFD2 blade on me and I need to split kindling? From what I seem to understand, the spine isn't that hard, so it could withstand the blows, but what about the edge under such circumstances? I guess this is sort of a "what if' scenario, but opinions on normal D2 are such that a knife in D2 would be inappropriate for such work... (and no, I am not suggesting using it to hammer through a car door! LOL!!!) But just something that may occur in a slightly adverse situation a hunter may experience on a hunt gone bad...

And I do look forward to hearing any updates y'all provide as you explore the process of FF!

PS: Would Friction Forging have any additional benefits to any of the other steels used in knife making? If the process breaks crystalline structure into finer crystals; wouldn't that be beneficial to any of the other steels used? Or maybe even in bonding two different steels together as in some of the blades which are appearing with the edge of one kind of steel "zippered" together with another? Just curious!

Thanks again!

(Please pardon my thread drift here... If needed, I would not mind the Mods maybe splitting this off and starting a more appropriate thread??? )

 

[Alberta Ed]

Oh, great... just what I need, another blade to buy. Thanks, guys.

 

[tnelson]

Thanks for the info, Tracy! :thumbup:

I guess my only other question (please excuse me if this was addressed in the other threads, as I'm about to read them,) but how does FF affect D2 with respect to impact stresses? Specifically, chopping? I see that some have found it to be adequate to cut bone in the butchering process, but suppose I only have a 5" FFD2 blade on me and I need to split kindling? From what I seem to understand, the spine isn't that hard, so it could withstand the blows, but what about the edge under such circumstances? I guess this is sort of a "what if' scenario, but opinions on normal D2 are such that a knife in D2 would be inappropriate for such work... (and no, I am not suggesting using it to hammer through a car door! LOL!!!) But just something that may occur in a slightly adverse situation a hunter may experience on a hunt gone bad...

And I do look forward to hearing any updates y'all provide as you explore the process of FF!

PS: Would Friction Forging have any additional benefits to any of the other steels used in knife making? If the process breaks crystalline structure into finer crystals; wouldn't that be beneficial to any of the other steels used? Or maybe even in bonding two different steels together as in some of the blades which are appearing with the edge of one kind of steel "zippered" together with another? Just curious!

Thanks again!

(Please pardon my thread drift here... If needed, I would not mind the Mods maybe splitting this off and starting a more appropriate thread??? )

Joeshredd,

Not recommended. However, to see what it could do, I used the first FF D2 prototype to chop all the wings and legs of my pheasant and chukars last year. I also used if for a wood chisel one day because my good wood chisel chipped. I hit the spine of the blade with a hammer which created a slight dent in it, but the cutting edge showed no damage.

I also watched one of the guides at the Tejon ranch use the FF blade to cut right down through breast bone of a wild bore. I thought it would chip or roll the edge, but I inspected and saw no damage and it still shaved. These are abuse stories, I do not recommend it for these nice knives.

With regards to your second questions: yes, and yes (might see them next year.).

Tracy

 

[Frank Hillary]

Hi Folks,

I dont know if this is right thread to ask this, but does D2 have any advantages over M2?

Seems to me that hi speed steel may be just the ticket. Just asking

Thanks fro any thougts

Frank

 

[Esav Benyamin]

Frank, it depends on the specific use. For example, many customers were very happy with Benchmade's 710 in M2, but it is hard to maintain. Now they use D2, which while technically not stainless, does not rust easily. In a folder carried in a pocket, used throughout the day, not always easy to stop to clean, a more stainless steel can be a better idea. In applications where maintainence is not a problem, M2 might be better.

 

[sodak]

Hi Folks,

I dont know if this is right thread to ask this, but does D2 have any advantages over M2?

Seems to me that hi speed steel may be just the ticket. Just asking

Thanks fro any thougts

Frank

If rust and staining is not a concern, my tests indicate that M2 at 65 HRC will hold an edge in abrasive materials (dirty rope, hide) about 3 - 5 times longer than D2 at 60 HRC. This is also dependent upon geometry of the edge.

 

[Frank Hillary]

Hi Folks

Thanks for your replys. My experience witha camilus stileto in D2 is that it blunts more esily than blades I made from discaraded tool steel saw blades which I think were M2. For rust, the D2 seems to be no better or worse. Just my experience.

Regards
Frank

 

[Mountainman38]

Last night I decided to buy an Ontario RAT-7 http://www.ontarioknife.com/adventure.html, I just liked the blade profile. That knife is made of 1095 or D2. I know 1095 takes a great edge, but darned if I know if D2 does. So I looked at this thread, and at the end of it, was not really certain which way to go.

So I decided on rust resistance. D2 it is. Hope I make the right choice. I am not going to be chopping trees or boulders with the thing. Probably the heaviest duty will be cardboard. All I want is just want a good sharp knife that is reasonably easy to sharpen.

Hope I did not mess up.

You sure didn't! Ive been using my RAT7 D2 for several months now, and I love it. I use it in the kitchen for chopping vegetables and fruit, in the garage for slicing cardboard, and in the woods for clearing brush and blackberry vines.

As for using it as a hard use knife -- I've chopped through 4" logs with it, and had no problems whatsoever. It's not as efficient as a larger knife would be, but it's a lot easier to carry than a machete. I wouldn't use it on rocks or metal, of course, and haven't tried prying with it. I figure I'll use it for cutting and chopping, and leave the prying to a crowbar.

 

[joeshredd]

Joeshredd,

Not recommended. However, to see what it could do, I used the first FF D2 prototype to chop all the wings and legs of my pheasant and chukars last year. I also used if for a wood chisel one day because my good wood chisel chipped. I hit the spine of the blade with a hammer which created a slight dent in it, but the cutting edge showed no damage.

I also watched one of the guides at the Tejon ranch use the FF blade to cut right down through breast bone of a wild bore. I thought it would chip or roll the edge, but I inspected and saw no damage and it still shaved. These are abuse stories, I do not recommend it for these nice knives.

With regards to your second questions: yes, and yes (might see them next year.).

Tracy

Tracy,
Thanks for the answers and I do look forward to seeing your product line develope! Am also going to keep my eyes open for any and all reports concerning y'all's knives and their performance... Very interesting potential!