稀土及卷取后冷速对高强钢板组织及第二相的影响

Effect of Rare Earth and Cooling Rate on the Microstructure and the Second Phase of High Strength Steel Plate

利用金相显微镜、扫描电镜、维氏硬度仪、X射线衍射仪、物相分析等检测手段研究了600℃卷取温度下,稀土及卷取后冷速对高强热轧钢板组织及第二相的影响。结果表明,试样卷取后,不同的冷却速度对稀土高强钢第二相的析出和组织有影响,对于1#(稀土含量30×10^-6)高冷速下的第二相析出比低冷速要更加均匀,但是析出相的数量要少析出54.5×10^-6,对于2#钢(稀土含量80×10^-6)低冷速下的第二相析出比高冷速多析出13.6×10^-6。在同样冷速下冷却到400℃后析出相的数量达到最大值,继续冷却后析出相数量基本不会变化。

In this paper,effect of rare earth and cooling rate on microstructure and the second phase of high strength hot rolled plate at coiling temperature of 400 ℃ was studied by means of metallographic microscope,scanning electron microscope (SEM),Vickers hardness tester,X ray diffractometer and phase analysis. The results showed that after coiling,different cooling rates have influence on the precipitation and microstructure of the second phase of rare earth high strength steel. The second phase precipitation of sample 1 (rare-earth content 30 ppm) at high cooling rate is more uniform than that at low cooling rate. However,the number of precipitated phases at high cooling rate is reduced by 54. 5 ppm. For steel 2(rare earth content 80 ppm),the second phase precipitation at low cooling rate is 13. 6 ppm more than that at high cooling rate. After cooling to 400 ℃ at the same cooling rate,the number of precipitated phase reaches the maximum,and is not changed basically after continuous cooling.