STAINLESS STEEL EXCELLENT IN RESISTANCE TO HIGH-TEMPERATURE CORROSION IN THE PRESENCE OF CHLORIDE

摘要

PURPOSE:To obtain an economical austenitic stainless steel excellent in resistance to high-temp. corrosion in the presence of chlorides, by specifying a composition consisting of C, Cr, Ni, Mn, Si, and Fe and also by regulating a grain size to a specific value. CONSTITUTION:The stainless steel has a composition consisting of, by weight, =0.03% C, 10-20% Cr, 10-30% Ni, =2% Mn, 1-6% Si, and the balance Fe with inevitable impurities and further has a structure whose grains are as fine as to have grain size No. (JIS) 6 or above and in which the total corrosion index represented by an expression 24.4Cr+2.8Ni+6.7Mn-48.8Si-56.9 Mo-148.0N is regulated to =500. This stainless steel has superior resistance to high-temp. corrosion in the presence of chlorides. As components for the above steel, one or more kinds among 0.5-5% Mo and/or 0.02-0.4% N, 0.1-1%, in total, of one or more elements among Ti, Nb, Zr, and Ta, and 0.001-0.1%, in total, of one or more elements among Ca, Mg, Al, Y, and RE can further be added selectively, if necessary.