保温时间对中碳钢组织及织构演变的影响

Effects of Holding Time on the Evolution of Microstructure and Texture of Medium Carbon Steel

采用Gleeble-3500热模拟试验机进行了双道次压缩变形实验,研究了在不同的保温时间条件下,经压缩变形后的中碳钢组织与织构的演变规律,探讨了保温时间对碳化物球化、铁素体回复再结晶、铁素体晶粒尺寸以及织构演变的影响。结果表明:随着保温时间的延长,铁素体逐渐发生回复与再结晶,碳原子的扩散能力逐渐增强,初始短棒状渗碳体的曲率半径逐渐减小,最终转变为球状碳化物。保温120min时,碳化物的球化效果最为显著,组织最为均匀。

The evolution laws of microstructure and texture of medium carbon steel after compression delorma tion under the condition of different holding time were studied by means of the double-pass compression deformation experiment conducted on the Gleeble-3500 thermal simulation testing machine. The effects of holding time on carbide spheroidizing, recovery and recrystallization of ferrite, ferrite grain size, and evolution of texture were discussed. The results showed that, with the extension of holding time, recovery and recrystallization of ferrite occurred gradually, the diffusion ability of carbon atoms became stronger, the radius of curvature of initial short rod cementites became smaller, eventually transformed into globular carbides. When holding time was 120 min, the spheroidizing effect of carbides was the most significant,resulting in the most uniform microstructure.