Why CPM 4V? Cause it sounds cool?
Nah, there is a thought behind it
lets go indepth,
While learning more about CPM M4 for puukkos and its use in competition blade sports, I was curious why CPM M4 dominated that arena.
So I began talking to Donovan Phillips, 2016 Bladesports Champion, who won this year using a CPM M4 chopper blade at 60HRC
I noticed that bladesports competitor
Dan Kleffler had a few videos up talking about
Vanadis 4 Extra, a Bohler Uddelohm company, third generation (MicroClean®) powdered metal, carbon tool steel with more strength, wear resistance and high working hardness but less toughness then the CPM 3V that is almost a household name in the fixed blade community as "the steel to have" ( doesnt interest me since impact toughness is not needed on a 3.4 inch blade and we can get more performance in other alloys)
The blades that Dan was using were heat treated in collaboration with Brad at Peter's Heat Treat.
From my conversations with Brad it was found out that V4E could achive higher toughness at 64 hrc then CPM M4 at 60 hrc,
thats crazy.
unfortunately, BU stopped hot rolling sizes for knife makers and have made it
very difficult to have access to that steel. Sometimes thats just how it works, the knife community is not at the forefront of cutting edge technology there is a huge disconnect between the metallurgists, manufacturers, knife makers, knife sharpeners and the knife users.
so its difficult to explain why something is worth the investment when it comes to talking to companies that only do BIG business to make a small batch for "some dude"
anyway turns out Crucible has also made a similar alloy much like what they did with CPM 20CV ( which is actually an alloy they bought from the defunct Latrobe metal corp) which is an analog of Bohler M390
C
PM 4v, which is basically a "sister" steel to the V4E but with minor variation in the alloying and most notably is using the first Gen. Crucible Particle Metallurgy® or CPM which has a the coarsest powder of the there major steel companies BU being the finest and Carpenter Metals MicroMelt® being in between the two.
finer powder, finer carbide
in honesty, I have not found a way to test the differance between similar alloys by these different companies using different powder sizes. (dont have the money)
in theroy, the first gen. can produce a more aggresive edge while third gen. should have more potenial with a higher polished edge and may be tougher.
who knows, so many variables.
CPM 4v also suffers avaliblity issuses as well, which is why it isnt being used in the m4 dominated bladesports arena, but it is at least avalible in Puukko sizes
IN-Depth info about PM steel
understand that all the PM process does is spread out the alloys that form the small globs that are harder then the surrounding steel known as CarbidesNOT the Grain size which is still determined by the Time and Temperatures of the heat treatment which determines how the Iron crystals change shape and grow.
Carbides are result of the carbon and (for example) vanadium making atomic bonds that are very strong and hard with vanadium having an independent hardness of approx. 82 hrc versus the Martensite in steel only being able to achieve 62hrc with higher carbon steels relying on Cementite or "iron carbide" which can push 65hrc
http://www.crucible.com/eselector/general/generalpart1.html
lay mans terms, it cuts longer, and is a harder steel that is stronger and can hold its shape better verus a more simple alloy that is can have more plastic like deformantion and ductilty but doesnt cut as long or hold its shape or edge as long.
Moving on,
talked to Brad about what I wanted with the heat treatment.
These Puukkos are at 64 hrc
This isnt a well devolped steel for knife makers. What I mean is that no one knows what the best heat treatment protocols are for this steel
Heat Treatment is the best kept secret as to why knives perform better then others and is the part of that "big three" geometry, steel and heat treat yet is the most difficult aspect to comprehend
CPM 3V (unlike CPM 4v) has been well devoloped and is very popular and well known which definetly helps it "snowball"
I'd argue that the guys with the best heat treat on CPM 3v being the one devolped by Brad @ Peters Heat Treat (PHT) , Dan Keffeler (bladesports) and
Nathan Carothers (Carothers Knives) after 10 years of trial and error. which is also being used by Guy at survive knives under the intellectal properity of Brad and the others by PHT
These guys are very inspiring to this puukko project I feel they are the some of the many pioneers of our generation pushing the envelop with PM tools steel metallurgy used for knives, it is the main reason that 4v is chosen, however we dont need as much toughness as 3v but rather more edge holding
these Puukkos will be .170 at the thickest point but zero ground to .010 behind the egde with a mircobevel.
Unlike M4, ive never used CPM 4V so I dont know anything from personal experience to share with you all and the production market is very slim with options to test.
So we will all learn together.
it is my hope to play with this steel more and see whats possible.
can we get a higher working hardness then 64hrc? can we get an even finer grain structures? not sure
but tomorrow we go live.
all thanks to
"Puukkoseppa" Danjiel Haramina Malanika Who is also just as curious and passionate as I am to see whats possible with the latest alloys and metallurgy
My only part in this project is just being a very obsessesd knife nerd thats just charming enough to get Daniel excited enough to work his magic on these awesomes steels and make sweet puukkos out of them.
Well, Ihope that gives a look into my brain as to why this steel was chosen for over some others.
we can discuss and compare the chemistry of 4v versus 3v and M4 if you guys are curious as well
Thanks
Shawn
