430铁素体不锈钢板坯组织分析

采用金相显微镜(OM)对430铁素体不锈钢板坯宏观组织和金相组织进行检测，采用X射线衍射(XRD)和差热分析的方法对板坯中物相进行分析，并用电子探针(EPMA)确定铸坯中元素分布。结果表明:430不锈钢铸坯试样在加热过程中发生了铁素体和奥氏体的相变，X射线衍射图谱中只有体心立方的α相峰位；430不锈钢板坯宏观组织由柱状晶和等轴晶组成；板坯金相组织由铁素体基体和长条状、块状的马氏体组成，存在成分偏析；柱状晶区金相组织中马氏体质量分数为30％，而等轴晶区金相组织中马氏体质量分数为14％。

Structure analysis of 430 ferritic stainless steel slab

The macrostructure and microstructure of 430 ferritic stainless steel slab were studied by means of optical microscopy (OM).The phase was analyzed by means of X-ray diffraction (XRD) and differential scanning calorimetry-thermogravimetric(DSC-TG) tests ,and the element distribution was determined by electron microprobe (EPMA). The results show that phase transformation of ferrite and austenite happened in the heating process of 430 ferritic stainless steel specimens; XRD patterns of 430 ferritic stainless steel slab was α phase with body-centered cubic; macrostructure of 430 ferritic stainless steel slab was composed of columnar grains and equiaxial crystal grains; microstructure of 430 ferritic stainless steel slab was composed of ferrite matrix and martensite with shape of long strip and block,and the composition segregation was existing; the mass fraction of martensite in the area of the columnar crystal was 30％,while the mass fraction of martensite in the area of the equiaxial crystal was 14％.