Method for manufacturing thin steel plate for sandwich steel by using strain induced transformation and sandwich steel

摘要

A method for manufacturing a thin plate of an outer plate for an ultra lightweight sandwich steel plate using a modified organic transformation and a sandwich steel plate are provided. The present invention provides a process for producing a steel sheet, comprising the steps of: preparing a TRIP steel sheet whose internal structure contains ferrite, bainite and retained austenite; A step of cold-rolling the TRIP steel sheet at a cold reduction ratio of 50 to 70%; A step of recrystallizing and annealing the cold-rolled steel sheet in an abnormal temperature range of 750 to 830 ° C; Quenching the recrystallized annealed steel sheet to a temperature range such that its internal structure has a residual austenite of 20 to 40% by area; And forming the deformed organic martensite structure in the internal structure by molding the quenched steel sheet in accordance with the shape of the outer plate to thereby produce a thin plate of the outer plate for the ultra lightweight sandwich steel sheet using the modified organic transformation.