Originally Posted by
Derek Cohen
I have minimal knowledge of metallurgy, so bear with my feable reasoning.
First off, are there different qualities of A2? Steel should be made to a recipe, and I gather that A2 steel has 5% chromium to increase wear resistance. By comparison, stainless steel has 10.5% chromium. Adding more or less carbon, chromium, moly and vanadium will affect steel properties differently. Now if all steel manufacturers used the same formula for A2, we could rule out one variable. So the first question is whether all make A2 steel the same way, and that we may expect this area to be uniform?
The second issue is how the steel is hardened and tempered. Is this also to a recipe? Can we expect the A2 steel from LV to be the same as LN and anyone else?
It is only at this point that we may evaluate bevel angles, since increasing a bevel angle may disguise inadequacies/differences in a steel.
Even if steels are prepared the same way, there are still rogue blades with brittle edges. Brittle is what leads to chipping. Indeed any chipping is a result of the edge lacking elasticity (tensile modulus), that is, it is too rigid. Powdered steels, such as PM-V11, are engineered to offer a finer grain structure along with -greater tensile modulus, which should (and does in my tests) offer greater resistance to chipping when hammering chisel edges into hardwood. PM-V11 may also be more safely used at lower bevel angles (as low as 20 degrees).
It seems that there is more at work than fine grain structure alone, however, since simple carbon steel alone is not that wear or impact resistant. However it is more likely to roll than chip, unless the edge is brittle (from grinding or heat treatment). That is when one adds chromium to beef it up, and it turns into A2 or M2, etc.
So before we start blaming A2, we need to know whether all A2 is expected to be the same - because if it is not, then we need to look at reliability factors, that is, from whom the steel is likely to do as promised.
Anyone answer these questions?
Regards from Perth
Derek