Bohler M398 steel

Mo2 · Apr 27, 2019

C - 2.7%, Cr - 20%, Mo - 1%, V - 7.2%, W - 0.7%, S - 0.5i%, Mn - 0.5%

-some notes from random Russian forum posts... take with a grain of salt.
So far, this steel is only in diameters 35.8 and 38
Rounding up, 74euro per kg
Rolling is not an option, they write that during cold rolling is prone to cracking.

-Denis Frolov has some m398 roundbar stock. check out his instagram
https://www.instagram.com/yanhook151984/

-Link to the pdf converted to English using an online translator.
https://www.scribd.com/document/407854724/Bohler-M398-Ru-en

-The original russian pdf link from Bohler.
http://www.bohlernn.ru/media/Bohler_M398.pdf

Found a few vids too, but i dont know russian.

dirc · Apr 27, 2019

of course, first thing we should do is page

Larrin

but personally, I just wouldn't use cast iron to make a knife... even with pm tech
it's like zdp189 but with 7% vanadium added - which of course makes it really nice wear resistance wise... it should put zdp189 to shame

but it still suffers the cracking / lack of toughness issue, which in real world use is just a real pain

it would be interesting if they dropped the carbon in half, or even went down to 0.8% - then it might be like 3v on steroids ; )

DeadboxHero · Apr 27, 2019

Looks wild, take notes boys, this is how you share an interesting steel. Give useable information to think about.

Any ideas on where to get?

Mo2 · Apr 27, 2019

DeadboxHero said:
Looks wild, take notes boys, this is how you share an interesting steel. Give useable information to think about.

Any ideas on where to get?

http://www.bohler.com.ua/en/contact-bohler-ukraine-1178.php
One of the Russian forums provided that link. You also met CultroTech who work with yanhook151984 aka Denis. You can try and contact them possibly. Maybe they can bring some to blade if they are going. Otherwise I don't have any more info at this time. If you know a bohler rep, you might be able to contact them to see when they might be getting it. Since it comes in round bars, it'll take some time to mold it into a knife.

hugofeynman · Apr 28, 2019

In my humble opinion, if a steel can’t be cold rolled to a bar/sheet in a desired thickness, given this bar/sheet the optimal grain direction/orientation, it has no use for knives. If you’re making a 1/2” thick monster with a thick edge, not a big deal, but for a nice cutting piece of cutlery, it will not be good. Regarding this steel, I would much prefer Vanadis 4 extra Superclean or even Vanadis 8, if extra wear resistance (cutting soft material) is your main goal, both from a sheet cold rolled in the Mill to a knife thickness and the blank cut parallel to the rolling direction of the steel. Cutting a bar to make one knife from a big round piece is doable, just need a nice saw, but you won’t get the full advantages of that particular steel, far from it, because grain microstructure would be far from optimal.

chumaman · Apr 28, 2019

hugofeynman said:
In my humble opinion, if a steel can’t be cold rolled to a bar/sheet in a desired thickness, given this bar/sheet the optimal grain direction/orientation, it has no use for knives. If you’re making a 1/2” thick monster with a thick edge, not a big deal, but for a nice cutting piece of cutlery, it will not be good. Regarding this steel, I would much prefer Vanadis 4 extra Superclean or even Vanadis 8, if extra wear resistance (cutting soft material) is your main goal, both from a sheet cold rolled in the Mill to a knife thickness and the blank cut parallel to the rolling direction of the steel. Cutting a bar to make one knife from a big round piece is doable, just need a nice saw, but you won’t get the full advantages of that particular steel, far from it, because grain microstructure would be far from optimal.

same technique as Denis Frolov

Larrin · Apr 28, 2019

Very interesting, looking forward to writing about it. Looks like the toughness is very poor. I’ve been waiting for a new steel to write about.

dirc · Apr 28, 2019

in that video, if you pay close attention, it took him 50+ heats of the round stock just to get it to the usual starting point of a bar...

imho, that's a bit extreme

hugofeynman · Apr 28, 2019

chumaman said:
same technique as Denis Frolov

I’m sorry for my ignorance, but Bohler can’t forge this steel to sheets because of the risk of cracks, but this gentleman can forge it to a knife shape with no cracks?

Silent H · Apr 28, 2019

hugofeynman said:
I’m sorry for my ignorance, but Bohler can’t forge this steel to sheets because of the risk of cracks, but this gentleman can forge it to a knife shape with no cracks?

It's stated that Bohler can't "cold roll" this into sheets. As the name implies, cold rolling is done at the end of the process when the steel is cold, in order to form the bar stock (I think there are a few other reasons for doing it as well, I barely got a passing grade in my basic materials course so I'm definitely not an expert.) You can't really compare it to forging since they're done at different temperatures, and it would probably be cost prohibitive for Bohler to forge all of this into bar stock, especially when all of the "areas of use" in the company literature involve the use of round stock.

chumaman · Apr 28, 2019

Denis and this blacksmith used principles of low temperature forge described here-http://www.kuznec.com.
obvious the Russians successfully forged steels which I also know are very difficult or impossible

Mo2 · Apr 28, 2019

hugofeynman said:
I’m sorry for my ignorance, but Bohler can’t forge this steel to sheets because of the risk of cracks, but this gentleman can forge it to a knife shape with no cracks?

As I said those were comments from a forum. Take with a grain of salt. As more information develops, we will learn more from Bohler themselves if that is true or not.

Mo2 · Apr 29, 2019

chumaman said:
Denis and this blacksmith used principles of low temperature forge described here-http://www.kuznec.com.
obvious the Russians successfully forged steels which I also know are very difficult or impossible

Is this the article you mention?
http://www.kuznec.com/failure_of_steel.html

If so, Its very hard for me to understand it, even with Google translate.

dirc · Apr 29, 2019

that is really quite interesting, it seems that kuznec is talking about dealing with microfractures as a feature of blade forging, to make it stronger by avoiding the build up of fractures internally by using 3 key elements:
1. very weak hammer strikes, don't try to move a lot of material with big swings
2. very low temps
3. acorn shaped hammers (I guess a smaller ball peen hammer should work) as this will not allow fractures to form, giving steel a direction to move which does not induce build up of fractures

He seems to be making the point that doing all this will result in a steel which is less dense AND stronger?? (this part I might not be understanding)

it would interesting to hear

Larrin talk about this, from a more scientific perspective

Larrin · Apr 29, 2019

dirc said:
that is really quite interesting, it seems that kuznec is talking about dealing with microfractures as a feature of blade forging, to make it stronger by avoiding the build up of fractures internally by using 3 key elements:
1. very weak hammer strikes, don't try to move a lot of material with big swings
2. very low temps
3. acorn shaped hammers (I guess a smaller ball peen hammer should work) as this will not allow fractures to form, giving steel a direction to move which does not induce build up of fractures

He seems to be making the point that doing all this will result in a steel which is less dense AND stronger?? (this part I might not be understanding)

it would interesting to hear Larrin talk about this, from a more scientific perspective

I do have an article on forging of steel coming out today. I'm not particularly interested in whatever he is saying about changing the density or strength of the steel, however.

chumaman · Apr 29, 2019

https://www.instagram.com/yanhook151984/

Larrin · May 6, 2019

I published my analysis of the steel: https://knifesteelnerds.com/2019/05/06/bohler-m398/

scott.livesey · May 6, 2019

So if you are maker of screw auger plastic/ceramic extruders or screw fed plastic molding machines, we have the steel for you. I love the tease in the Bohler brochures, showing knife blades, even knowing they are not making sheet stock at this time. Move over Maxamet, M398 is a coming.

Mo2 · May 7, 2019

scott.livesey said:
So if you are maker of screw auger plastic/ceramic extruders or screw fed plastic molding machines, we have the steel for you. I love the tease in the Bohler brochures, showing knife blades, even knowing they are not making sheet stock at this time. Move over Maxamet, M398 is a coming.

Honestly, it's more of a knife steel than you think. It may never leave Russia, who knows. They don't seem to have issues making knives in it. And I remember when knives were hand forged. Thing of the past these days?

While it may dethrone maxamet, how will it compare to rex121 in edge retention? Which seems to be available as some customs are being made of it from sheets. So, we may not even have a need for it per say.

DeadboxHero · May 7, 2019

Mo2 said:
Honestly, it's more of a knife steel than you think. It may never leave Russia, who knows. They don't seem to have issues making knives in it. And I remember when knives were hand forged. Thing of the past these days?

While it may dethrone maxamet, how will it compare to rex121 in edge retention? Which seems to be available as some customs are being made of it from sheets. So, we may not even have a need for it per say.

I'd rather have the Maxamet. More stable. That's pretty gnarly when you can say that Maxamet is more edge stable than something.