The martensite in low and medium carbon alloy steels mainly is lath martensite of dislocation substructure besides little twin substructure at the segregation regions of chemical composition.

• 低、中碳合金钢中的马氏体除局部区域因成分偏析呈孪晶亚结构外,主要是位错亚结构的板条马氏体。低碳合金钢的中温转变组织主要有兰类,即粒状组织、上贝氏体和下贝氏体。