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利用扫描电镜(SEM)和电子背散射衍射技术(EBSD)对马氏体以及铁素体+珠光体组织中碳钢在550℃双向温轧后的组织演变进行了研究。结果表明:淬火马氏体温轧后渗碳体颗粒在铁素体基体上分布比较均匀,小角度晶界所占比例很高,4道次轧制后亚晶粒尺寸约为1.35μm,部分铁素体晶粒发生动态再结晶,形成大角度晶界包围的细小的等轴晶粒;而铁素体+珠光体作为轧前组织,温轧后渗碳体颗粒和亚晶粒主要集中在原珠光体区,4道次后平均亚晶粒尺寸约为1.79μm,等轴细小的铁素体晶粒主要在原珠光体与铁素体边界分布。双向温轧是淬火马氏体获得碳化物颗粒与超细晶铁素体均匀混合组织的有效方法。
The microstructure evolution of martensite and ferrite + pearlite carbon steel after two-way warm rolling at 550 ℃ was studied by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The results show that the cementite particles are distributed uniformly on the ferrite matrix after being tempered by quenching martensite, and the proportion of small angle grain boundaries is high. The subgrain size after 4 passes is about 1.35μm, The dynamic recrystallization of the ferrite grains leads to the formation of fine equiaxed grains surrounded by the large-angle grain boundaries. While the ferrite + pearlite as the pre-rolling microstructure, the cementite grains and subgrains are mainly concentrated in the original pearlescent After 4 passes, the average subgrain size is about 1.79μm. The fine equiaxed ferrite grains are mainly distributed on the boundary between the original pearlite and ferrite. Bidirectional warm rolling is an effective method for obtaining homogeneous mixed microstructure of carbide particles and ultrafine-grained ferrite by martensite quenching.