Is A11 really the best at holding an edge?

Sam- Welcome to the forum. I think you are referring to this particular page?
http://www.timken.com/products/specialtysteel/engineering/tech_info/html/Knife Steels.htm
It is generally good to approach a manufacturers own numbers with some suspicion, especially when stacking theirself up to the competition. According to the chart above BG42 at 60rc has twice the wear resistance of m2 at 63 RC and D2 at 61 RC?!!!!!
Their reference to 'powder metallugy'' process for their 'DuraTech A11' sounds like their version of CPM process, still those numbers are remarkably high. If we take their own numbers at face value I think 'Duratech NINE' is even more interesting for knife makers:
http://www.timken.com/products/specialtysteel/engineering/tech_info/html/DuraTech_A11.htm
But those numbers for wear resistnace, A11 at 63 Rc = 15 TIMES more wear resistant over D2 at 62 and M2 at 65 RC???!!!!!!!!! Wow! :eek: Perhaps too good to be true?!!!
Stil it would be good to hear comments from some "experts"
Thanks for the links- interesting-
Martin
 
A11 is CPM-10V. Yes the wear resistance difference is that high. No this doesn't lead to a direct gain in edge holding. No it isn't the highest, there is CPM-15V, CPM-125V and even things like CPM REX 121.

Edge holding is dependent on many factors; hardness, wear resistance, impact toughness, ductility, corrosion resistance, grain size, etc. . How much of a factor these various properties influence depends on the type of material being cut and the method used. To see the most gains from wear resistance you will want to be cutting very abrasive material like used carpet and doing it in an even and controlled manner.

On a lot of other materials other factors could be the dominant ones. For the vast majority of the materials normally cut with a small utility knife, hardness is more important to edge holding.


-Cliff
 
That makes more sense if A11 is cpm10V, still numbers like BG42, 60RC having 2x wear resistance to D2, 61 RC and M2, 63 RC- that doesn't make sense.
So is A11 their own version of 10V? isn't the powder metallurgy process propritery?? or does Timken Latrobe buys it from CPM ???
Curious-
Martin
 
CPM-10V is AISI A11, they are the same steel. It is like oui and yes are the same word just in two different languages. More companies than Crucible are making powdered steels. A quick check of the website shows that Latrobe is a steel manufacturer and not just a reseller.

BG42, 60RC having 2x wear resistance to D2, 61 RC and M2, 63 RC- that doesn't make sense.
Click to expand...

Hardness has little effect on wear resistance which is primarily due to carbides. BG-42 has a very high alloy content which is centered on very hard carbide formers. It has more V, Cr, and Mo than D2, and much more C and Cr than M2 with just a little less V.

Spec's do change though from one place to another. For example ASM lists the wear resistance of 440C as 2 with M2 at 7 and D2 at 8. The above linked chart has 440C much closer, only ~25% or so behind M2. It is difficult to estimate off of the chart.

Wear resistance can be adhesive or abrasive and could also be effected by variables such as speed of grinding, so for a rigerous comparison you would want more details of exactly how the tests were done.

As well, you would also want to know the exact heat treat cycle for the steels. Just knowing the RC, while informative, doesn't tell you the whole picture. You can get to a hardness in multiple ways which can have very different other materials properties.

-Cliff
 
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