K390 Military

Mr. Wilson,
From your experience, although possibly limited, I have a question.

On a scale of 1-10, with S90V being one, where would you place M390 S390,, K390, 10v 15V, S125V and finally CPM Rex 121?

Thank you for sharing your knowledge and experiences with us. :thumbup:

Ben
 
Phil Wilson said:
On the discussion of CPM 10V and Bohler-Uddeholm K294 here it was mentioned here that 10V has stupid good wear resistance but lower toughness than K294. Not to step on your toes Blackcatt but I personally have not seen that. They are both the A11 grade and the same chemistry. I think Ankerson tested both and has some data on that. It more depends on the heat treat and edge geometry. The BU particle process is more refined but the particle size on both is so small that I am not sure the difference would show up in a knife blade. I like both steels, CPM 10V is like 40 years old since development and over this time they have worked out all the potential problems. This BU version is very nice indeed, heat treats easy and the finer grain and advertised cleaner mix are all welcome. Both companies have been very helpful to us custom makers. Good tech support and availability of steel. They are also willing to supply material in small quantities and thickness that work for a knife blade.
The K390 is an interesting change. As mentioned before it is the A11 grade basically but with added tungsten and moly. Both these form carbides that add to the vanadium carbide in the mix. The data sheet says a little less wear resistance than the std A11. I guess that is because both moly and tungsten carbide are slightly softer than vanadium carbide. On the basis of one knife blade I did not see that K390 has less edge holding than 10V or K294. They are all very good, in fact in the same top category and I think it would take a laboratory and very controlled conditions to see a difference. BU has mentioned that they are going to do some CATRA tests with K294 so when that comes out maybe it will tell us something. K390 has the potential of inching the hardness up a bit with a thin edge geometry or a more aggressive use with the same geometry. We may be talking about marginal differences but as more makers work with K390 we should get some feedback. I just ordered some to play with and will have more to say as I get some experience with it. A kitchen knife is a good place to start.
If Sal makes a folder with CPM 10V, K390 or K294 I will be in line for one. Phil
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Not at all Phil, that's good news to me. Having never tried the K294 I was just making a guess. If there were any difference I'm sure it would be very small.

Edit: looking back at the post I made it kinda looked like I was saying 10V had much less toughness than K294...I was comparing A11 grade to K390, and just supposing K294 might be marginally tougher than 10V due to the more advanced processing. Certainly not trying to run down 10V. I've used it a lot and only had great results. I'll stick to my direct experience to serve the discussion better.
 
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Ben, I have no direct experience with 15V and Rex 121 and do not know about S390. Maybe you mean K390. That leaves M390, S90v, 10V. If you are asking just about edge holding based on the best hardness for each and the same edge geometry, cutting rope for example then it would be in the order of CPM 10V (A11) at RC 64, CPM S90V at RC 60 and M390 at RC 62. I would say that S90V and M390 are very close in some comparisons. S90V has more vanadium carbide for wear resistance but M390 with less carbide can be pushed a little harder. Both really good steels. I really boils down to what is best for the application. Phil
 
Phil Wilson said:
Ben, I have no direct experience with 15V and Rex 121 and do not know about S390. Maybe you mean K390. That leaves M390, S90v, 10V. If you are asking just about edge holding based on the best hardness for each and the same edge geometry, cutting rope for example then it would be in the order of CPM 10V (A11) at RC 64, CPM S90V at RC 60 and M390 at RC 62. I would say that S90V and M390 are very close in some comparisons. S90V has more vanadium carbide for wear resistance but M390 with less carbide can be pushed a little harder. Both really good steels. I really boils down to what is best for the application. Phil
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Thank you for the information, sir. It's appreciated!:thumbup:
 
Ben, Yup, have made it and will continue to use it. I used it on a hunting trip in September. It is in the kitchen right now. I ordered enough steel to make some more. Phil
 
That is good news indeed!:D:

Perhaps after the expenses involved with the Holiday season have been borne, I may reconsider the long wait, and contact you directly.

Thank you for all of the information you have provided on this subject. It is truly appreciated. :):thumbup::)
 
How would k390 fare in ultra thin cutting-edge applications like a straight razor? The edge holding would be a boon, and the thinness might make honing bearable. The question is whether it would actually take that fine an edge with 9% vanadium?
 
Rsq said:
How would k390 fare in ultra thin cutting-edge applications like a straight razor? The edge holding would be a boon, and the thinness might make honing bearable. The question is whether it would actually take that fine an edge with 9% vanadium?
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K390 is a third generation powder metal steel, so the vanadium carbides are quite small. I would also be quite interested in an authoritative answer to that question! :p
 
blackcatt said:
Just saw this thread after a buddy alerted me of it.

Corrosion is about like M4.
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That kinda kill it for me. In fixed blade yes, no problem but in folder I would gladly exchange toughness for corrosion resistance. The reason I am not using my M4 Millie is that one have to spend too much time to baby it after each apple cut and life is short :)
 
I too find that I have to baby my M4 Military, but I will probably continue purchasing carbon steel and tool steel blades.
 
Don't know about all of that, I use my K294 blade in the kitchen and I don't baby it and haven't even started to see any kind of patina yet.

That 3rd generation steel is very clean so one really doesn't have to worry too much about corrosion, no more than normal care is needed.
 
Ankerson said:
That 3rd generation steel is very clean so one really doesn't have to worry too much about corrosion, no more than normal care is needed.
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i feel the same about cpm M4. it's not 1095, pretty far from this actually. once you have used it a bit it takes a even, light and gray-ish patina that stays here and barely evolve ... and it's not that easy to rust.

my M4 milie is holding just fine and i even dipped my gayle bradley in ferric chloride because i was frustrated by it's lack of patina after 6 month of occasionnal EDC.
 
I regularly cut apples and oranges, and such with M-4. I wipe it lightly with a handcherchief, and wash and dry it at the end of the day. Thus far, I have experienced no corrossion problems whatsoever with my M-4 Military, of my M-4 mule.
 
I recently received a fixed blade in K390. I've used it on thick cardboard (refrigerator box), plastic security strips used on pallets, food and clam shell type plastic. The edge holding it phenomenal! Granted I've only had it for approx 30days but it shows no signs of dulling anytime soon. I really cannot compare it to the knives I have in S90V, M390, M4 and CTS-20CP just yet.
As for the patina, it developed a light grey one in about 2wks but I used some automotive polish to remove it and have coated the knive in a homemade brewed mixture of carnuaba, beeswax and orange oil. Nothing sticks to it now ;)

Here is the knife I'm speaking off http://www.bladeforums.com/forums/showthread.php/897134-New-EDC-fixed-blade-in-K390-by-David-Williamson?highlight=k390
 
capid1 said:
]I recently received a fixed blade in K390. I've used it on thick cardboard (refrigerator box), plastic security strips used on pallets, food and clam shell type plastic. The edge holding it phenomenal! Granted I've only had it for approx 30days but it shows no signs of dulling anytime soon[/B]. I really cannot compare it to the knives I have in S90V, M390, M4 and CTS-20CP just yet.
As for the patina, it developed a light grey one in about 2wks but I used some automotive polish to remove it and have coated the knive in a homemade brewed mixture of carnuaba, beeswax and orange oil. Nothing sticks to it now ;)

Here is the knife I'm speaking off http://www.bladeforums.com/forums/showthread.php/897134-New-EDC-fixed-blade-in-K390-by-David-Williamson?highlight=k390
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Now, if we could just get a Military made from this stuff..................:thumbup::D:thumbup:
 
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