Abstract: A titanium-clad steel and a method for its manufacture are disclosed. The titanium-clad steel comprises a steel base metal, a nickel insert which is bonded to the steel base metal, a low-carbon ferrous metal insert which contains at most 0.01 weight % of carbon and which is bonded to the nickel insert, and cladding of a titanium-based metal which is bonded to the low-carbon ferrous metal insert. A manufacturing method therefor comprises preparing a 4-layer clad assembly comprising the above materials, sealing the outer seams of the clad assembly by shielded arc welding, performing degassing treatment on at least the confronting surfaces of the inserts, heating the clad assembly to a temperature of 500.degree.-1050.degree. C., and performing hot rolling. The resulting titanium-clad steel has a high bonding strength.

Abstract: The present invention relates to the austenitic steel having improved resistance to oxidation at the high temperature, comprising not more than 0.10% C, 0.1-5.0% Si, not more than 3% Mn, 7-45% Ni, 15-30% Cr and sulfur content being restricted to not more than 0.003%. According to the present invention, by limiting the sulfur content in the austenitic steel to not more than 0.003%, preferably to not more than 0.0015%, the heat-resisting steel material which can show improved resistance to oxidation under severe conditions including repeated heating to high temperatures and cooling to room temperature is provided.

Abstract: A process for producing heat-resistant ferritic stainless steel sheet which exhibits improved toughness and productivity is disclosed. The process comprises the following steps:(a) hot rolling a steel with a finishing temperature of not higher than 850.degree. C., said steel comprising, by weight %,C: not more than 0.07%,Si: 1.5-3.5%,Mn: not more than 2.0%,Cr: 10-25% ,N: not more than 0.05%,Nb: 5X(C %+N %)-20X(C %+N %),optionally at least one element selected from the group consisting of Al, Y, Ca, and REM in a total amount of 0.3% or less, andthe balance iron and incidental impurities; and(b) annealing the resulting hot rolled steel sheet at a temperature of 820.degree.-1000.degree. C.Cold rolling may be applied to the annealed hot-rolled steel sheet.