That is quite a sufficient reference to chemistry, very similar to the one I reviewed in my materials book. Thanks fcc...

In the "old days" I don't think as much was known about the common alloying elements like chromium or the others like vanadium or moly. There wasn't good enough chemistry at that time to separate those because their melting temperatures, to isolate them from the iron ore, were too close to the iron. Where silver and the other metals, they had a much larger experience working (since before the iron age) and could easily separate them by melting temperatures.