EFFECT OF COOLING RATE ON MICROSTRUCTURE AND CENTERLINE SEGREGATION OF A HIGH-STRENGTH STEEL FOR SHIPBUILDING
Ultra-fast cooling(UFC)has been increasingly applied in industry,but accompanying with great changes of rolling strategy.It is therefore of importance to evaluate the characteristics of steels produced by UFC as compared to those processed by conventional accelerated cooling(ACC).The present study examines the microstructure through thickness and centerline segregation of solute elements between UFC and ACC steels,both of which were rolled at a final rolling temperature at around non-recrystallized temperature.UFC steel showed the pronounced microstructural transition from lath-type bainite with Widmanst(a)tten ferrite at subsurface to acicular ferrite in an average size of~5μm dispersed with degenerate pearlite in the interior.In contrast,ACC steel had the homogeneous microstructure through the thickness,which was distinguished with coarser polygonal ferrite grains and pearlite nodules.Moreover,the centerline segregation was significantly suppressed by applying UFC at a higher cooling rate of 40 K/s compared to 17K/s for ACC steel.The significant differences in the microstructure and centerline segregation caused by various cooling rate is discussed from the view of γ→α transformation.
Ultra-fast cooling Grain refinement Microstructure through thickness Centerline
Qibin Ye Zhenyu Liu Guodong Wang
The State Key Laboratory of Rolling and Automation,Northeastern University,3-11 Wenhua Road,Shenyang,110819,China
国内会议
杭州
英文
365-370
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）