Abstract: Steel alloys having improved mechanical properties and improved ambient and low temperature toughness following the repeated thermal exposures necessary to fuse and bond ceramic or glass coatings thereto have been prepared. Phase transformation temperatures are controlled by a critical combination of manganese, silicon, and optionally, nickel, in a steel alloy of silicon, carbon, aluminum, titanium and/or niobium, phosphorus, sulfur and iron. The resulting steel alloys have good glassability, and even after glassing demonstrate excellent yield strength, ultimate tensile strength and impact strength at both ambient and low temperatures (-20.degree. F.).