Abstract: Taking continuous annealing production of cold rolled Q&P steel as the technological background, the heat treatment process of soaking and heat preservation in two-phase zone+slow cooling+rapid cooling to partitioning between Ms and Mf points was adopted, and the effects of different soaking temperatures in the two-phase zone on microstructure and mechanical properties of low-carbon silicon manganese alloyed Q&P980 high-strength steel were studied. The results show that with the increase of soaking temperature in the two-phase region, the ferrite content decreases, the proportion of martensite and lath size increases, the content of retained austenite first increases to 7.2% and then decreases. With the further increase of soaking temperature, the tensile strength increases monotonically due to the increase of martensite content in the matrix, while the change trend of elongation is similar to that of retained austenite content. When the partitioning temperature is 310 ℃, the best soaking temperature range is 765.24-812.56 ℃. When soaking at 790 ℃, the tensile strength is 1052 MPa, the elongation is 22.9%, and the strength-elongation production is 24 090.8 MPa·%.

Key words: continuous annealing, soaking temperature, Q&P980 steel, mechanical properties, retained austenite