中厚板边部裂纹形成机制

Formation Mechanism of Edge Crack for Medium and Heavy Plate

采用光学显微镜、扫描电镜以及能谱分析等方法对低合金中厚板边部裂纹形成机制进行研究。结果表明:中厚板边部裂纹的形成是由于在轧制过程中钢板边部表层出现低温组织;变形不均匀导致边部应力集中,以钢板次表层存在的皮下气泡或颗粒状CaO-SiO2-Al2O3夹杂物为裂纹源,萌生裂纹并扩展,形成中厚板边部多处断续出现的横向应力裂纹。

Systematic investigation on the formation mechanism of edge crack for low alloy medium and heavy plate was made by using optical microscope, scanning electron microscope and electron probe microanatysis techniques. The result shows that the edge crack of plate formed because of the over-cooling structure formed on the surface of plate in rolling processes and the inhomogeneous deformation lied to stress concentration at the edge of plate. The skin blowhole and CaO-SiO2-A12 03 inclusion in the subsurface layer of plate are crack sources~ crack initiation and growth, present intermittent occurred for multiple sites transverse stress edge cracks on medium and heavy plate.