Genuine Damascus steel: a type of banded microstructure in hypereutectoid steels

A brief review is given of the evolution of welded Damascus steel and genuine Damascus steel along with the mystery of how the pattern of genuine Damascus steel is produced. The prior studies claiming to have either, reproduced the genuine Damascus steel, or explained the mechanism of pattern formation, are reviewed. None of these studies have allowed modern bladesmiths to reproduce the steel. The author and a bladesmith, Alfred Pendray, have developed a process with which Pendray can produce blades that match the microstructures of the best museum quality genuine Damascus blades. Experimental research is reviewed showing that the microstructure of this steel is produced by an unusual type of banding that requires: (1) the presence of low levels of certain impurity elements in the hypereutectoid steels, with V being most effective, and (2) a thermal cycling heat treatment. A main difference of this type of banding and the ubiquitous banding of hypoeutectoid steels is point (2), the requirement of thermal cycling. A theory for the banding mechanism is presented.