chrome steel

Chromium forms chrome steel, and with the further addition of nickel is called chrome nickel steel.

The bars used in modern jails and prisons are often made in a similar manner of alternate sheaths of iron and chrome steel.

When used for safes and money vaults this steel has one great advantage over chrome steel—it is not affected by heat.

Against attacks of the sledge, however, it is probably inferior to chrome steel.

Well, Tema, old son, we're prisoners as surely as though we were locked in a chrome steel vault a thousand feet underground.