What do you choose? Is it 58/59 HRC super powder metal (m390, elmax MagnaCut, etc.) or 62/63 HRC D2, Sleipner or similar steel?

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whereismyknife

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To keep all variables constant, let's talk about a specific model and let's call it crk sebenza. What would you prefer, a 58/59 hrc super steel or a 62/63 HRC D2/sleipner? I would love to know your thoughts.
 
I stil use a lot of D2 steel at work. It's cheap and more then good enough for certain applications/tooling. Usually I don't go higher then 60HRc.
62 to 63HRc D2 knife? I'm not sure. At this hardness D2 steel becomes fragile and prone to chip. I have never used Sleipner so I can't comment. I personaly would go for a super steel.

Say; is this just hypothetical question or someone really hardens D2 knives to 63HRc?
 
TheOne45 said:
I stil use a lot of D2 steel at work. It's cheap and more then good enough for certain applications/tooling. Usually I don't go higher then 60HRc.
62 to 63HRc D2 knife? I'm not sure. At this hardness D2 steel becomes fragile and prone to chip. I have never used Sleipner so I can't comment. I personaly would go for a super steel.

Say; is this just hypothetical question or someone really hardens D2 knives to 63HRc?
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You are right, but when the blade size is small, for example a Sebenza size, D2 is not that fragile. I've seen D2 with this hardness (62hrc) before. I haven't even seen it personally, but I read a post on a local forum from someone who claimed to have seen 65 HRC. I don't know if it's true.
 
whereismyknife said:
You are right, but when the blade size is small, for example a Sebenza size, D2 is not that fragile. I've seen D2 with this hardness (62hrc) before. I haven't even seen it personally, but I read a post on a local forum from someone who claimed to have seen 65 HRC. I don't know if it's true.
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It's possible. Here is from hudsontoolsteel.com: "For maximum wear resistance, temper between 300-350°F (149-177°C) for a hardness of 62-64 HRC. For the optimal balance between wear resistance and toughness, temper between 500-550°F (260-288°C). This will produce 58-60 HRC.".

I don't mind D2 if I like a knife. Just prefer Sleipner, feels like Cruwear.
 
I have several knives in D2 have held up very well, a Dozier Thorn that is supposed to be 60-61HRC, and a Horton TAC-4 in CPM-D2 at 62 HRC, and a couple of fixed blades from Brad Cartwright that I believe are at 59-60 from how they touch-up on my paper wheels.
I also have some older models from Kershaw (Speedform, Leek, Rake) with composite-bladed CPM-D2 edges. Those I find are actually more difficult to sharpen, but I rarely have to do that and I just strop them on leather with some diamond spray.
I haven't found any chipping issues with any of them.

I have a custom chef knife from Marcin Bona in CPM D2 as well, HT'd to 62-64 HRC and I've never had to resharpen that at all. A little patina has formed on the blade.
I also have other custom kitchen knives in non-stainless (W2 at 64HRC, 15n20 at 61HRC) and they're amazing performers albeit with more pronounced patinas.

I don't have any supersteels softer than 60 HRC, and most of those in that range are S90V (custom/production/folders/fixed) as HRC doesn't need to be that high for that steel.
I also have some productions and customs in other supersteels at 65HRC+ : a couple of Spydercos in Maxamet @ 66+, a couple in K390 at 65+, and a couple of customs with REX121 @ 69-70.
I can't say that the higher HRC blades are better, the REX121 knives have thick stock and took a lot of time to reprofile, but have stayed sharp with just a touchup on a strop loaded with diamond spray. The Maxamet and K390 blades are thin and slicy, but I haven't used them hard to where I'd be worried about chipping.

As far as preference, a properly heat-treated stainless supersteel like S90V pretty much covers everything I need.
 
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whereismyknife said:
You are right, but when the blade size is small, for example a Sebenza size, D2 is not that fragile.
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Blade itself is not that fragile. You would need to put some large force in it to break the blade in half.
But edge is different story. Try hitting a nail with the 63HRc D2 edge.
If you look steelnerds graph 'toughness vs hardness' D2 is at the bottom of the graph.

But I like D2 steel. My working knife has K110 blade at 60.9HRc (measured in our lab on very fancy machine) .
 
Back in the day, a limiting factor of CPM 420V (S90V) was attainable hardness, which was recommended by the manufacturer to be 58-59 RC. This was mainly due to the limitations of HT furnaces of the time. I have my S90V run at 61.5-62RC, maximized for cutting and edge retention not toughness. There is no reason a "super steel" designed for maximum cutting should not be run hard. And if you are making a chopper out of it...reconsider your steel choice. If I were making a 5" blade hunter from S90V I might run it at 60-61 RC, but that would be the lowest I would go.


Interestingly, you will still see some suppliers that recommend 58-59 RC for 90V....
 
TheOne45 said:
Try hitting a nail with the 63HRc D2 edge.
If you look steelnerds graph 'toughness vs hardness' D2 is at the bottom of the graph.
Click to expand...

I don't think I will need this in daily life, so having a D2 knife chipping on the edge of the blade doesn't worry me, but I understand what you mean and I agree. Sleipner is a pretty good steel in this regard.
 
oldrifleman said:
Why would I pick a Super Steel that is sold "soft? Most the ones you listed (M390, Elmax and Magnacut) are normally run in the 62/63 HRC range.
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There are threads about some companies heat treating these steels to low hardness. The ones that come to mind are medford and crk, I may be remembering wrong.
 
navman said:
Back in the day, a limiting factor of CPM 420V (S90V) was attainable hardness, which was recommended by the manufacturer to be 58-59 RC. This was mainly due to the limitations of HT furnaces of the time. I have my S90V run at 61.5-62RC, maximized for cutting and edge retention not toughness. There is no reason a "super steel" designed for maximum cutting should not be run hard. And if you are making a chopper out of it...reconsider your steel choice. If I were making a 5" blade hunter from S90V I might run it at 60-61 RC, but that would be the lowest I would go.


Interestingly, you will still see some suppliers that recommend 58-59 RC for 90V....
Click to expand...
What you said is exactly what raises the question in my mind. In my opinion, it is not right to keep super steel at low hardness levels to make it tougher. Of course, I'm not saying hardness is everything, but don't we expect these from super steels? Isn't that the point of paying so much money? Just as you pointed out, I still see premium steels with low hardness from some manufacturers.
 
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