PROCESS FOR PRODUCING A FERRITIC STAINLESS STEEL WITH IMPROVED CORROSION RESISTANCE, IN PARTICULAR RESISTANCE TO INTERGRANULAR CORROSION AND PITTING CORROSION

摘要

The present invention relates to a process for producing a ferritic stainless steel having improved corrosion resistance, and in particular resistance to inter granular corrosion and pitting corrosion. Steel, produced in the form of a slab, contains in its weight composition: 18% chromium 27% 1% molybdenum 3% 1% nickel 3% manganese 1% silicon 1% carbon 0.030% nitrogen 0.030% 0.075% titanium 0.20% 0.20% niobium 0.50% sulfur 0.01% phosphorus 0.1% the rest being iron and impurities resulting from the fusion of the necessary materials during production, is subjected, in a first phase, to cooling at a speed of between 400.degree.C and 600.degree.C / hour to the temperature of 900.degree.C, then, in a second phase, rapid cooling at a speed between 1200.degree.C and 1400.degree.C / H.