Abstract: A heat-resistant austenitic stainless steel is disclosed. This steel essentially consists of: not more than 0.06% C, 1-4% Si, 0.5-4% mn, not more than 0.035% P, not more than 0.005% S, 10-17% Ni, 14-20% Cr, 1-4% Mo, 0.01-0.5% Al, not more than 0.035% N, and balance essentially Fe, and may further contain small amounts of any of Cu, REM and B and the composition thereof is adjusted so that a limited amount of .delta.-ferrite appears in solidification. The steel has excellent hot salt corrosion resistance, weldability, salt errosion resistance of the weld and hot-workability.

Abstract: Ferritic stainless steel consisting essentially of, in % by weight, 0.0050 to 0.0500 of C, 10.00 to 18.00 of Cr, up to 0.50 of Si, up to 0.50 of Mn, more than 0.040 but not more than 0.200 of P, up to 0.030 of S, up to 0.60 of Ni, 0.005 to 0.200 of Sol. Al, and 0.0020 to 0.0050 of B, the balance being Fe and impurities, and having a longitudinal cracking transition temperature of not higher than -10.degree. C. as determined by the cup expansion test hereinbefore described. The steel has excellent formability and secondary workability.