Quote Originally Posted by Caledonian View Post
...Almost all modern damascus blades use different steels in layers which could mean a hair encountering more than a hair's breadth of one alone in the cutting edge. If different hardness survives the welding, anything that isn't good enough for a razor on its own isn't good enough to be part of a damascus razor. In a knife for some applications, such as cutting meat, a microscopic saw-toothed effect may be very useful. but a razor is different.

For similar reasons, I don't believe acid etching is appropriate in a damascus razor. In the sort of microphotography which you sometimes see on this board, I believe it would look like teeth interpersed with areas of honeycomb.
I entirely agree that the steels used in PW material should each be able to stand alone as a functional material. But you argue in manner suggestive that this is somehow a common occurrence amongst the majority of PW makers, or that PW steels by themselves are all suspect for this problem. On this point, I disagree. This thread began and ends with the concern that quality controls with Pakistani PW steels have generated reputational problems.

The hardening process is an entirely separate operation that occurs after the assembly of the billet. Briefly, the carbon content homogenizes (usually by the third or fourth welding pass) across all the different materials in the billet, except pure nickel - which will not harden regardless. Nothing about welding the steel affects the hardenability of those materials. There are other significant processes involved preparing the material welded for heat treatment later. By that point, with a microhardness tester, it should be shown that all layers have the same hardness, driven by the carbon content and not the minor alloying elements that produce the contrast in layers.

Microserrations are more likely from the grinding abrasives than a feature of the PW steel itself, especially if the myth of hard and soft layers dies the death it so richly deserves.

Any microserrations would also likely disappear in the honing and polishing of the edge before shaving with such a blade. Any pattern, etched, would also disappear during the establishment of the bevel and subsequent honing/polishing and preparation of the edge to shave.

A fair test would be to try several of the suspect steel mixtures, several well established "good" tool steel recipes, hone them up and see what happens, via photomicrographs, after a suitable interval of testing across several face types. I don't have access to a microhardness tester (capable of testing the hardness of individual carbide crystals) but would be very interested in adding this as a variable if it were possible.