690合金管冷轧及退火处理过程中的组织演变

Microstructure evolution during cold rolling and annealing treatment for alloy 690 tube

利用光学金相显微镜和扫描电子显微镜研究了690合金一次冷轧管在中间退火过程中的组织演变规律,以及不同固溶处理制度对690合金二次冷轧管(成品尺寸管)的晶粒度和碳化物回溶行为的影响,并建立了退火过程中再结晶晶粒长大方程。试验结果表明:一次冷轧管中间退火最优工艺是1100℃/5 min,所建立的晶粒长大模型预测结果与实验值吻合很好,成品管经1100℃/3 min固溶后,平均晶粒尺寸在23.5μm左右,晶粒组织均匀,碳化物完全溶解。

Microstructure evolution of single-pass cold rolled alloy 690 alloy tube during intermediate annealing and effects of different solid-solution treatments on gain size and dissolution of carbides in the finished size tube were studied by means of optical microscope（OM） and scanning electron microscopy（SEM）,and the model and dynamic equation of recrystallized grain growth during annealing were established.The results show that the optimal intermediate annealing process for the cold rolled tube is at 1100 ℃ for 5 min.The grain size predicted by the proposed grain growth model well agrees with the experimental results.Uniform grains（average grain size about 23.5 μm） are observed in the alloy 690 solid-solution treated at 1100 ℃ for 3 min with full dissolution of carbides.