Abstract：In order to produce a kind of TRIP980 with excellent surface quality and comprehensive mechanical properties，stating from the view of economization and lightening，the composition design idea of low silicon，adding phosphorus and vanadium micro-alloying were tried to use. And the decrease of hot rolling temperature was used，supplemented by the subsection cooling mode（laminar cooling＋air cooling＋air mist cooling）. The results indicates that the microstructure of TRIP980 steel is consisted with（44.0%-49.3%）ferrite，（37.0%-42.8%）granular bainite and （13.2%-14.0%）retained austenite（volume percent）. More than 81.5% grain sizes are less than 4.0 μm. Meanwhile，the high dislocation density existed in matrix and the nano-sized precipitates of V（C，N） with diameter of 2-5 nm are distributed dispersively. Under the interaction effect of strengthening mechanism which included the phase transformation strengthening，fine grain strengthening，precipitation strengthening and dislocation strengthening，the excellent combined mechanical properties are achieved. Rm≥1 096 MPa，A80≥23.2%，n≥0.24，the hole expanding rate is no less than 90%.
2019, Vol. 54 
