Abstract: The hot plasticity of S32750 dual phase steel (/% ：0. 20C,25. 50Cr,7. 05Ni,3. 50Mo,0. 28N) casting and solid-solution condition columnar zone and equiaxed zone at 1 000 ~ 1 200℃ is studied by Gleeble thermal. The results obtained elongation and reduction of area of the steel at 1 100 - 1 150 °C are best. With the analyzed by SEM, the S32750 steel is brittle fracture at 1 000 〜1 050 ℃,tough fracture at 1 050 ~ 1 150 ℃. and intergranular failure at 1 150 - 1 200 ℃. And the crack of S32750 steel is along interphase at 1 000 ~ 1 050 ℃ , and along intergranular boundaryat 1 150-1 200 °C. The optimum thermoplastic temperature of S32750 steel is determined to be 1 150-1 200 ℃ by integrating the thermal simulation test.

摘要： 利用Gleeble试验机研究S32750双相钢(/%:0.20C,25.50Cr,7.05Ni,3.50Mo,0.28N)区铸态和固溶态柱状晶和等轴晶区在1000～1200℃的热塑性,表明得出该钢的延伸率和断面收缩率在1 100～1 150℃最佳。通过电镜分析,在1000～1 050℃ S32750钢呈脆性断裂,在1 050～1 150℃呈塑性断裂,在1 150～1200℃为沿晶断裂。S32750钢1 000～1 050℃ 时裂纹沿相界,1 150～1 200℃时裂纹沿晶界。综合热模拟试验,确定S32750钢的最佳热塑性温度为1 150～1 200℃。