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The continuous annealing simulator was used to investigate the influences of annealing temperature on mechanical properties of a high strength hot-dip galvanizing MP980 steel.Base on these simulation process above,the key process for industrial production of hot-dip galvanizing multiphase steel of 980MPa grade has been established.The microstructures and mechanical properties of industrial trial productswere investigated by means of mechanical properties testing,optical microscope(OM),the multiphase structure as well as dislocation distribution and precipitation behaviors of second-phase particle for the controlling of mechanical property uniformity of hot-dip galvanizing MP980 steel are also researched by transmission electron microscope(TEM).The results shown that the yielding strength rises as the annealing temperature increases,the stress-strain curve of experiment steels exhibited continuous yielding feature after different annealing process,under the appropriate intercritical annealing conditions,the microstructures of the experiment steel consisted of nearly polygon ferrite,bainite,fine dispersed distribution martensite and retained austenite islands.The dislocation density decreases gradually from the ferrite-martensite interface and ferrite grain boundary to the inner part of ferrite.There are two different sizes and types of precipitates,one type is small dispersion precipitate with size of 15~50nm,the other type of precipitates is square shape with size of 50~200nm.The experiment steel has the comprehensive performance with the tensile strength of 1039MPa,yield strength of 776MPa,elongation of 12#,at the intercritical annealing temperature of 800℃,slow cooling temperature of 700℃,rapid cooling temperature of 460℃and the cooling rapid rate of 35℃ per second.It is believed that martensite grain dispersed refinement distribution and precipitation strengthening are main factors contributing to high strength of steel sheet.These off-line products reached the same level of mechanical properties as the imported products through two times industrial trial and have been successfully applied to some joint venture vehicles.