METHOD FOR MANUFACTURING FLAT STEEL PRODUCTS FROM A STEEL FORMING A MARTENSITIC STRUCTURE

摘要

#CMT# #/CMT# The method for the production of flat steel products useful in automotive industry, comprises casting a steel into a cast strip having a thickness of 1-4 mm, hot-rolling the cast strip in-line into a hot-rolled strip having a thickness of higher than 1.5 mm in a continuous process at 900-1050[deg] C, and coiling the hot-rolled strip at 550-620[deg] C to obtain a hot-rolled strip, which has a minimum tensile strength R m of 1400 MPa and a minimum breaking elongation A 8 0 of 5%. The hot-rolled strip is cold-rolled with a thickness of 0.5-1.4 mm at 750-850[deg] C to obtain a cold-rolled strip. #CMT# : #/CMT# The method for the production of flat steel products useful in automotive industry, comprises casting a steel into a cast strip having a thickness of 1-4 mm, hot-rolling the cast strip in-line into a hot-rolled strip having a thickness of higher than 1.5 mm in a continuous process at 900-1050[deg] C, and coiling the hot-rolled strip at 550-620[deg] C to obtain a hot-rolled strip, which has a minimum tensile strength R m of 1400 MPa and a minimum breaking elongation A 8 0 of 5%. The steel forms a complex phase structure. The shaping degree is greater than 20%. The width of the hot-rolled strip is more than 1.600 mm. The hot-rolled strip is cold-rolled with a thickness of 0.5-1.4 mm at 750-850[deg] C to obtain a cold-rolled strip, which has a minimum tensile strength of 600 MPa and a minimum breaking elongation A 8 0 of 15%. The cold- or hot-rolled strip is provided with a metallic coating, which is galvanizing. #CMT#USE : #/CMT# Method for producing flat steel products useful in automotive industry. #CMT#ADVANTAGE : #/CMT# The method allows production of high-tensile flat steel products with less effort in a wide range of geometric dimensions. The produced steel product reduces the weight of the vehicle and ensures safety to the vehicle during collision. #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Components: The steel contains 0.15-0.19 wt.% of carbon, 1.80-1.20 wt.% of manganese, = 0.030 wt.% of phosphorus, = 0.004 wt.% sulfur, 0.60-1.00 wt.% of silicon, = 0.05 wt.% of aluminum, = 0.0060 wt.% of nitrogen, 0.30-0.60 wt.% of chromium, 0.040-0.070 wt.% of niobium and the remainder being composed of iron and inevitable impurities.