METHOD OF MANUFACTURE OF TWO-LAYER HOT-ROLLED SHEETS WITH MAIN LAYER MADE FROM LOW-CARBON STEEL AND CLAD LAYER MADE FROM CORROSION-RESISTANT STEEL Russian patent published in 2001 - IPC

FIELD: metallurgy; manufacture of equipment for oil and chemical engineering and other industries where corrosion-resistant structural members are required. SUBSTANCE: method consists in control of temperature and deformation parameters of rolling of two-layer sheets ensuring obtaining fine grains in metal of main layer, conducting one-stage heat treatment (annealing) at temperatures ensuring elimination of faults at interface of layers, obtaining equilibrium microstructure of main layer, transformation of martensite in structure of clad layer into ferrite-carbide mixture. To this end, rolling of two-layer sheets is complete at relative draft in last pass of 5 to 30 % at temperature assigned in accordance with the following relationship: T_t.r.= (770+800×%C)±40, where T_t.r. is temperature of termination of rolling, C; % C is content of carbon in steel of main layer, %-mass; cooling the hot-rolled sheets to at least temperature of 500 C is conducted at rate of 0.1 to 40 C/s and annealing is performed at temperature ranging from 670 to A_c1+50^°C, where A_c1 is critical point of steel of main layer. EFFECT: enhanced strength of two-layer sheets; reduced heat treatment time at retained ductility, viscosity and adhesion strength and corrosion resistance of clad layer. 2 tbl, 1 ex