铁素体钢中白点缺陷的检验分析

 通过金相显微镜、扫描电镜等分析方法对铁素体钢低倍检验后发现的疑似白点缺陷进行了分析判断，发现疑似白点缺陷在金相显微镜下呈锯齿状裂纹，为白点裂纹形貌特征。通过对低倍试样上断口的检验发现，低碳铁素体钢宏观断口处分布有银灰色圆形斑点，为白点缺陷特征，铁素体不锈钢宏观断口无明显白点特征，但铁素体不锈钢的疑似白点显微断口有沿晶断裂和以夹杂物为裂纹源的解理断裂两种，都具有氢脆断口特征，由此判断，两种铁素体钢中缺陷均为白点缺陷。铁素体不锈钢中的白点缺陷与常见白点断口上的浮云状、波纹状、解理羽毛、显微疏松等形貌特征有所不同，而且不同铁素体不锈钢试样上的白点缺陷断口形貌也不同，一处为沿晶断裂，一处为以夹杂物为裂纹源的解理断裂。

Inspection and analysis on flakes defect of ferrite steel

Suspect flakes defects in ferrite steel were analysed by OM and SEM. The results showed that the suspect defects appeared zigzag crack，which is the characteristic of flake crack. According to fracture analysis，at macro fracture of low carbon ferrite steel was distributed silver grey and round spot，which is the characteristic of flake defect，and there was no flakes defect characteristics at macro fracture of ferrite stainless steel. However，the fractographic of suspect flakes of ferrite stainless steel was intergranular fracture and cleavage fracture as the source of inclusions，which two are characteristics of hydrogen fracture. In conclusion，the suspect flakes defects in two ferrite steel were all flakes defect. The morphology features of flakes defect in ferrite stainless steel was different from normal flakes defect such as clouds，rippled wall， clavage feathers，microporosity and so on，and the morphology of flakes defect in different samples of ferrite stainless steel were different. One was intergranular fracture，the other was cleavage fracture as the source of inclusions.