Abstract: At present，the phenomenon of uneven cooling in the width direction of slab was ignored in the dynamic secondary cooling control model and dynamic soft reduction model of slab continuous casting. The nozzle had the problems of poor atomization effect，serious nozzle blockage，small nozzle adjustment ability and unstable spray angle. The hinge point type sector segment had poor roll gap accuracy and difficult to assemble and disassemble，which cannot meet the requirements of modern continuous casting technology for high roll gap accuracy and reducing maintenance cost. To solve the above problems，an online simulation model of three-dimensional temperature field，a new type of high-efficiency nozzle，and a new type of gapless roll gap adjustment segment were developed and applied in many engineering fields. After upgraded，the detection pass rate of cast slabs was increased to 99.5 %，and the incidence of transverse cracks，longitudinal cracks，and corner cracks on the surface of cast slabs was reduced by 53.96 %，56.3 %，and 29.19 % respectively. The offline calibration of the segment and the online control of the roll gap accuracy were increased by more than 2 times，and the installation and disassembly time of the segment was reduced by 66 %.

Key words: slab continuous casting, three-dimensional temperature field, high-efficiency nozzle, segment, clearance-free