MULTI-PHASE STEEL OF MAXIMUM STRENGTH WITH IMPROVED PROPERTIES IN THE PROCESS OF MANUFACTURE AND PROCESSING

摘要

1. Method for the production of cold or hot rolled steel strip from multiphase steel of ultrahigh strength with combined characteristics, in particular suitable for creating vehicles with low weight, the required multiphase microstructure, which is formed during continuous annealing, and the steel includes elements, wt.% : C from 0.075 to ≤0.105Al from 0.005 to ≤0.060Si from 0.200 to ≤0.650Μn from 1.750 to ≤2.350Ρ≤0.020S≤0.0050Cr from 0.200 to ≤0.500Mo from 0.200 to 0.500Ti from ≥0.005 to ≤0.060 Nb from ≥0.005 to ≤0.060V from ≥0.005 to ≤0.060V from ≥0.0010 to ≤0.0060N≤0.0090 the rest is iron and not impurities, characterized in that the cold or hot rolled steel strip in a continuous annealing furnace is heated to a temperature of from 700 ° C to 950 ° C and then the annealed steel strip is cooled from the annealing temperature to a first intermediate temperature from 300 ° C to 500 ° C cooling rate from 15 to 100 ° C / s, then cooled to a second intermediate temperature from 200 ° C to 250 ° C at a speed of 15 to 100 ° C / s, then the steel strip is cooled in air at a speed of 2 to 30 ° C / s to ambient temperature or cool it at a rate of 15 to 100 ° C / s from p rvoy intermediate temperature to ambient temperature sredy.2. The method according to claim 1, characterized in that the molybdenum content is from ≥0.250 to ≤0.450%. 3. The method according to claim 1, characterized in that the niobium content is from ≥0.025 to ≤0.045%. The method according to claim 1, characterized in that the titanium content is from ≥0.025 to ≤0.045% .5. A method according to claim 1, characterized in that the vanadium content is from ≥0.015 to ≤0.045% .6. A method according to claim 1, characterized in that the boron content is from ≥0.0010 to ≤0.0050%. 7. The method according to claim 1, characterized in that the nitrogen content is ≤0.0070% .8. The method according to claim 1, characterized in that the total content of titanium, niobium, vanadium, molybdenum and boron is ≤0.590% .9. The method according to p. 1, characterized in that when galvanizing sp