steel plate has high mechanical characteristics and resistance to ductilite formabilite, manufacturing process and use of such plates

摘要

the invention relates to the production of a cold rolled steel sheet of higher strength to 1000 mpa, elongation over 12% over and above 90 pliabilitu00e9 v, whose membership includes the contents being expressed in weight: 0.15% = c 0.25%, 1.8% = mn = 3.0%, 1.2% = so = 2% 0% = 10% al, 0% = cr = 50%, 0% cu, 1% 0% = and = 1%, 0% = s -.0% 0% = p 20%, n = 0.015%, ti = 20%. v = 0.015%, k = 1%, n = 8). b = 0.001% as mn + ni + cu = 3%, the balance of the composition being iron and unavoidable impurities as a result of the development.the microstructure is formed in the area ratio of 5% to 20% of polygonal ferrite, 10 to 15% of residual austenite, martensite, 5 to 15%, the balance being made up of bainite lath form and including the lath carbides, such as the number of u00efnter lath carbides (size greater than 0.1 micron per unit surface area is less than or equal to 50 / 100.