My best guess would be something equal to our 10xx. Basicly, a simple steel of iron, carbon, and a little manganese, or not. To make cheap products, the first thing in importance is to use cheap materials. Not to say that the steel is poor, just that it is simple, and easy to produce. Nice job on the knife. Looks like pro work. Not a critique, but merely a simple tidbit of info. As far as I know, there are no documentable 18th c. knives with pewter bolsters, or mounts. The key being "documentable". I only know what I read, and have done a few myself knowing that, but sometimes one makes what sells. There are some that Madison Grant dated into the 18th c., but Grant is known to have been a bit "imaginative" with his dateing. At any rate, nice work, and you have a good eye for proportional balance.