Over here, silver steel refers to a very tough, bright carbon grade available in ground bar form- I've used a lot of it over the years for tool making, lock-picks, making small cutters and reamers etc. Worth it's weight for Locksmiths making their own tools, picks and wires. It's ready ground to incredible accuracy in metric and imperial sizes. It's easily hardened in brine or oil and easily tempered to just about any degree you want- it's amazing stuff. I've heard some say it tends to be brittle, but in all the tools I've made I've never had any problem. Stubb's is (or was) a big producer and is the brand that I've always used, but I'm sure there are many others. It's comparatively expensive stuff compared to black mild steel or bright bar though, and curiously it's always sold in 13 inch lengths and not 12.