08-27-2011, 12:48 PM
Nowadays, most freshly-made steel is the blue/grey colour which you noticed, Bernhard. Depending on the alloy and the finishing procedures, some will rust rather quickly, while other grades maintain that colour for quite some time. I'm guessing that in your 1900 era, though, that it wouldn't have been uncommon for more grades to form surface rust not long after being made.
Wayne
Wayne