CPM M4

B

bald1

Joined
Oct 3, 1998
Messages
1,646
Okay guys, here's the specs on CPM M4 which blows away regular M4. Might be interesting in a fairly large knife eh?

-=[Bob]=-

CPM® REX® M4HC(HS) (AISI M4)


Description
CPM REX M4HC (HS) is a high-vanadium special purpose high speed steel exhibiting
better wear resistance and toughness than M2 and M3 in cold work punches, die
inserts and cutting applications involving high speed and light cuts. The high carbon
(HC) modification to standard M4 is designed to provide optimum hardening response
in large cross-section tools or in vacuum or atmosphere heat treating. The high sulfur
(HS) modification is standard for large diameter bars providing enhanced
machinability and grindability.
Typical
Applications
Broaches
Large diameter screws
Granulator/Pelletizer Knives
Gear Hobs
Shaper Cutters
Shaving Cutters
Milling Cutters
Rolls
Punches
Dies
Chemistry
C 1.40
Cr 4.00
V 4.00
W 5.50
Mo 5.50
S 0.06(0.22)
Heat
Treatment
ANNEALING TEMP.
TYPICAL ANN. HDN. BRINELL
PREHEAT TEMP.
AUSTENITIZING TEMP.
QUENCH MEDIUM
TEMPERING TEMP.
TYPICAL APP. HARDNESS HRC.
1575/1425F
225/255
1500/1550F
1950/2125F
AIR/SALT
1000/1050F
60-64
 
When I was in the gear business a few years back we used rex all the time for the same applications as stated on the spec sheet. I think it would make a good blade if the back was drawn back to spring and the edge was about 58 for a big knife. Should be tough.. I still like the 420v alot.. great steel with a great structure. Any of the cpm steels 440v-420v-
and the super steels like you are talking about are great .
 
Got an e-mail from Spencer Stewert....he's engaged in a CPM M4 project now. Hopefully we'll get feedback on the finished blade here.

-=[Bob]=-
 
I have an affiliation with the CPM M4 project and you can expect to get all the details once I get a chance to wring in out. So far, it sure looks promising.

Sid

 
Hey all, a little update on the CPM M4 project. I sent this message to Sid Post earlier today. We have have some difficulty, more than originally expected on obtaining the steel. In the meantime, I have been neglecting (not entirely) my school studies and doing a little research in line with this and other projects of mine.

There is a missing part here. See below.

However, until further notice, I will continue to research other sources for this steel and various heat treatment services.>

Well, folks, there's your update. BTW, I would highly recommend (especially those who, like myself, are excited about trying out various steels for knifemaking) going to the library and checking out the above metnioned book, or another book of similar caliber (you will find several books written targeting junior high school and they may not contain the data you are looking for). This particular book is giving me enough meat to chew on for the time and does it in an understandable and useful way. Sometimes, in order to communicate particularly confusing concepts, the authors relay the message through analogies which really help digestion of the material.

Spencer Stewart

[This message has been edited by Spencer Stewart (edited 10-25-98).]

[This message has been edited by Spencer Stewart (edited 10-25-98).]

[This message has been edited by Spencer Stewart (edited 10-25-98).]
 
Here is the missing part from previous post:

Okay, now let me tell you a little of how I spent my weekend. Thus far
I've spent it reading TOOL STEEL SIMPLIFIED by Frank Palmer, George V.
Lueressen, and Joseph S. Pendleton. I haven't finished the entire book,
and it is a little dated (1978), but it does contain a lot of good
information. there is a valuable section in there on how to pick the
proper tool steel for the proper job and it is called the matched set
system. To save time, I won't go into details, unless of course
requested, but this is something I learned which is applicable to our
project. There are tool steels that are called "red" steels and these are
steels designed and alloyed to be able to do a prescribed task at high
temperatures which would normally ruin the tempers on regular tool steel.
The "M" series belongs to this group. CPM M4, though it has attractive
toughness and abrasion resistance, is alloyed and intended to operate at
temperatures approaching 1000 deg F. It is my hypothesis that due to the
added expense of this high-temperature tolerance, and it's intended niche,
CPM M4 may not be worth the money and time required, and we may be
somewhat dissappointed that the outcome isn't as superior as we once
expected.
 
DAMN. You mean its made for certain applications and not a good knife blade.
You means its a HSS. Damn. You mean it wont take the shock required for a knife thin edged blade? Well Im glad we got to the bottom of it..Just being a smart ass here
smile.gif


[This message has been edited by Darrel Ralph (edited 10-25-98).]

[This message has been edited by Darrel Ralph (edited 10-25-98).]
 
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