115W8 Steel Toughness | Chopping Through Brick | Low Alloy High Performance

[joshiecole]

115W8 is a steel that you don't hear much about on Bladeforums or for that matter anywhere else. I've been searching for steels that push the boundaries of edge retention and toughness for several years, and this steel is certainly an interesting addition to the discussion.

It's an extremely hard-to-come-by steel available from Germany. It's a very pure low alloy steel in the same vein as the Japanese steels, but is also noted for its good toughness at high hardness. Obviously relatively high toughness at high hardness offers very attractive impact resistance.

This is only a short video to give you an indication of the performance possibilities of this steel, but chopping through brick is a useful shorthand for impact resistance. As you can see from the video the knife is able to maintain a functional (paper slicing edge) in spite of being hammered through brick on my anvil. In actual fact this knife had been hammered through several other bricks even before the start of this video and left unsharpended, and you can see it had a functional edge at the start (as well as the end)

https://www.youtube.com/watch?v=R9uMbo31E94

Lot's of steels are tough, but this is interesting because its a high carbon tungsten steel (1.15% carbon) that offers quite impressive toughness at high hardness (62HRC).

Not a magic steel by any means, but definitely one to think about if you want impressive toughness at high hardness.

 

[dkb45]

I'm not even sure how the edge can be function after going through a brick. Every thing I thought I knew about knives says that a brick would wreck the edge, at least roll it, but it seems to have done little more than scuff the finish.

 

[joshiecole]

Here's a picture of the edge immediately after the video was taken. I like destruction testing videos but it's nice to get a still image of the edge afterwards. You can see the scuffs and it has not been touched up.

 

[Cobalt]

Funny, I just pounded an Mtech 151 into reinforced concrete trying to break it up and it hardly did anything to the edge and I was using an 8lb sledge with a lot more force. Even though bricks and concrete are hard, they fall apart fairly easily so a hard enough edge will survive it.

 

[joshiecole]

I actually started a thread a couple of years ago on the abuse that the mtech can take. I said at the time that it's a very tough knife for the money. In fact I repeated the same tests (more or less) with this knife. I cut through nails, hammered through concrete/bricks and hammered through 3 mm mild steel bar.

Like I said in the OP, there are lots of tough steels but the interesting challenge is to experiment with steels that can push out the performance frontiers in both directions (toughness and edge retention).

I have performed all of these tasks without breaking with the mtech but the mtech is hardened in the mid 50s and the 115w8 knife is hardened to 62. The mtech also has lower compression resistance and deforms more at the edge.

 

[Jens Schuetz]

Funny, I just pounded an Mtech 151 into reinforced concrete trying to break it up and it hardly did anything to the edge and I was using an 8lb sledge with a lot more force. Even though bricks and concrete are hard, they fall apart fairly easily so a hard enough edge will survive it.

I guess the first point of contact would get damaged and once a crack opens (which happens fast on concrete) the rest of the blade would be unaffected.
Still nothing I would wanna test with any of my blades. Glad if the maker tests it for his customers on his own risk.
I think there can be big differences, depending on steel , ht and prior micro damages, the kink on contact could be tiny or huge, simply roll or chip.

Also one question, why do many prefer rolling over chipping? I can't imagine that bending it one way and then bending it back will come anywhere near it's original strength.

 

[Cobalt]

The steel you used is very interesting and fairly high in Tungsten.

 

[jdm61]

I sometimes jokingly call 115W8 Hitachi Blue #1.5 because is has the carbon content of Blue #2 but the tungsten content of Blue #1. The only problem with the steel is its lack of availability. I used to be a fairly common steel for metal cutting bandsaw blades, but it was replaced in Germany with high speed steel. The thinking was that the HSS would last longer. That was correct in theory, but it assumed that you could keep the teeth from snapping off of the HSS blades. Most of this steel that we have seen recently came from a small "fun" batch smelted by Achim Wirtz at the Lohmann mill in Germany. Supposedly, you can take the stuff up to 64 for non "hard use" applications like kitchen knives.

 

[samuraistuart]

And if you can't find the 115W8.....go with the 110WCrV5 same as 1.2519, or O-7. Sister steel to 115W8. And slightly easier to obtain. Achim is the only source that I know of for the 115W8. Schmeideglut and Nordischez Handwerk carry the 1.2519. I also lovingly have termed 1.2519 "German Blue 2". An insanely tough steel for its hardness....and decent wear resistance as well.

To compare 115W8 to 1.2519:
Both have carbon similar at 1.1-1.2
1.2519 has slightly more Cr
1.2519 has some Moly and .5% Vanadium that 115W8 does not have
115W8 has slightly more Tungsten than 1.2519, but due to atomic weight of V vs W, the 1.2519 will have more carbide structure, because .5% V is akin to 1.5% W
1.2519 has Ni, which 115W8 does not
1.2519 has a bit more Si than 115W8
1.2519 has Mn count of 1.0, and 115W8 has much lower .2-.4

I think it is easy to see with this comparison......the wear resistance will go to 1.2519 (which I prefer for my knives...hunters and kitchen).
Toughness and fine grain will go to 115W8.

Been meaning to get more O7 in from Germany, maybe this thread will push me over the edge!

 

[joshiecole]

I don't believe in any one steel 'to rule them all', but I do believe that there are some steels that present particularly interesting answers to certain questions.

The question I was asking was what steels offer a novel balance of edge holding and toughness suitable for small adventure knives.

I started probing towards a slightly different balance of toughness and edge holding when I noticed that a few Busse users noted that they actually preferred 52100 in smaller knives. I was looking a steel which would take a very fine edge and maintain it very easily (stropping will do) and be more than capable of maintaining a functional (as Jens says bending isn't much better than broken or chipped) in the face of abuse. This was more or less the specific question I asked of Achim and he pointed me in this direction.

Anyway, I hope this has provided some interest for those of you like me who are always looking for interesting answers to the question of what makes a well balanced cutlery steel. If anyone is interested, I'd be happy to do another video chopping into some other stuff. These things can get a bit silly, but it's all part of the fun.

Btw, after a couple of drinks last night I ended up using the knife to make feathersticks for fire.

 

[samuraistuart]

Joshiecole, we ALL are after that bestest of the bestest steel, aren't we?!?!? All I can say is that I am a big fan of low alloy carbon steels, and as such the 115W8 is just simply a great one. If you want to do another video, bud, we WILL WATCH IT!!!!! I've only talked with Achim once online, at the time he didn't have any 115W8 (1.2442) for me, so I went with 1.2519 and haven't looked back. I don't know how well 1.2519 would stack against 115W8. My guess they would be so similar to tell apart. 1.2519 might have the "edge" in wear resistance, but that does not always translate to edge holding (apex stability). What is cut, how it is cut, can come into play when comparing. CPM M4 is about the highest alloy carbon steel that I play with...and I LOVE ME SOME M4, too. My only problem is my heat treat oven doesn't get hot enough for M4, so I'm limited to the lower alloy carbon steels, and knives that I make I simply MUST be in control of heat treat.

A couple of drinks last night? What were you sipping on? Fire....yeah....cool....he he....cool.

BTW, I think, not sure but almost sure, that 115W8 (1.2442) and 110WCrV5 (1.2519) both fall into the AISI O-7 label.

 

[joshiecole]

Joshiecole, we ALL are after that bestest of the bestest steel, aren't we?!?!? All I can say is that I am a big fan of low alloy carbon steels, and as such the 115W8 is just simply a great one. If you want to do another video, bud, we WILL WATCH IT!!!!! I've only talked with Achim once online, at the time he didn't have any 115W8 (1.2442) for me, so I went with 1.2519 and haven't looked back. I don't know how well 1.2519 would stack against 115W8. My guess they would be so similar to tell apart. 1.2519 might have the "edge" in wear resistance, but that does not always translate to edge holding (apex stability). What is cut, how it is cut, can come into play when comparing. CPM M4 is about the highest alloy carbon steel that I play with...and I LOVE ME SOME M4, too. My only problem is my heat treat oven doesn't get hot enough for M4, so I'm limited to the lower alloy carbon steels, and knives that I make I simply MUST be in control of heat treat.

A couple of drinks last night? What were you sipping on? Fire....yeah....cool....he he....cool.

BTW, I think, not sure but almost sure, that 115W8 (1.2442) and 110WCrV5 (1.2519) both fall into the AISI O-7 label.

Haha, I'll definitely admit that I'm always on the look out for the best of the best steel.... for my needs!

When I asked Achim about the main differences between 1.2442 and 1.2519 he said that 1.2442 was a bit tougher but that 1.2519 was less prone to staining. I for one would love to see what 1.2519 was capable of.

Personally I like low alloy steels. I like the way they take a very fine edge and are able to be maintained with minimal fuss even 'in the field'. And I reaaally like the tougher types.

 

[joshiecole]

Hi there, here are a couple of new test videos. There is one hammering through aggregate concrete and there is another being hammered through some 5mm thick mild steel. The quality of the videos isn't great, but hopefully they are able to give you a small impression of this steel. The stock of this test knife was only 3.3mm, so to be able to use it like a cold chisel was not too bad.

My own observations on this steel is that it is very good at resisting impacts, but its weakness (relatively) is side loads on the blade where it is bent forcibly or tangentially.

[video=youtube;mUwCDsWnXxI]https://www.youtube.com/watch?v=mUwCDsWnXxI&edit=vd[/video]

[video=youtube;Pq34kdY9_-M]https://www.youtube.com/watch?v=Pq34kdY9_-M[/video]

 

[joshiecole]

I've just rewatched the second video, and I really should apologize because you can't really see anything worthwhile. I just shot both tests and uploaded them without really checking whether they were useful.