横纵轧对低合金高强度钢夹杂物变形行为和低温韧性的影响

Effect of Cross Rolling on Deformation Behavior of Inclusions and Low Temperature Toughness in High Strength Low Alloy Steel

通过纵轧和横纵轧两种不同的轧制工艺,对夹杂物的数量、尺寸、形态进行控制。利用光学显微镜(OM)对不同轧制工艺下的组织形态和晶粒尺寸进行了分析,结果表明,在变形量相同的情况下,纵轧和横纵轧对组织形态和晶粒尺寸没有明显的影响。力学性能测试结果表明,两种工艺轧制的钢板具有相同的强度,但是横纵轧的钢板冲击性能低于纵轧的钢板,在-80℃低温下区别更加明显。利用OM和SEM对比分析了不同截面上的夹杂物,结果表明,两种工艺下差异最大的是MnS夹杂物。横纵轧钢板中,MnS沿轧向和横向两个方向变形,在纵截面和横截面上尺寸分布接近,有利于减轻各向异性;但MnS的最大长度没有减小,大尺寸MnS的数量也没有减少,因此-80℃下钢板的冲击功相对较低。

The quantity,size and shape of inclusions in the process of thermal deformation were controlled by two different rolling processes:longitudinal rolling and cross rolling.OM was used to analyze the microstructure and grain size under different rolling processes.The results show that unidirectional rolling and cross rolling have no obvious effect on the microstructure and grain size under the same amount of deformation.The mechanical properties test results show that the steel plates rolled by the two processes have the same strength.The impact properties of cross rolled steel plates are lower than that of unidirectional rolled steel plates,but the transverse and longitudinal differences are smaller,and this phenomemon is more obvious at-80℃.OM,SEM were used to compare and analyze the differences of inclusions in different sections.The results show that MnS inclusion is the biggest difference between the two processes.In cross rolled steel plate,MnS deform in rolling direction and transverse direction,and the size distribution is close in longitudinal section and cross section,which is beneficial to reduce anisotropy.The maximum length of MnS does not decrease,and the number of large size MnS does not decrease,so the impact energy of steel at-80℃is relatively lower.