高强船板低倍组织缺陷原因分析

对高强船板低倍组织腐蚀时产生的长条状开裂缺陷进行了研究分析。研究发现,钢板的拉伸、冲击断口均观察到撕裂状缺陷,这主要是由于铸坯的中心偏析引起的,其对钢的强度、低温韧性以及弯曲性能无明显影响。钢板在心部珠光体偏析带形成的细长条MnS是产生低倍腐蚀开裂缺陷的主要原因,钢板本身不存在任何开裂缺陷。

Analysis on Cause Leading to Defect of Macrostructure in Ship-building Plate with High Strength

When a ship-building plate is being corroded,strip cracking defect of its macrostructure occurred is studied and analyzed.Analytical results shows that the splitting-fracture defects appeared on the tensile and impact fractures of the plate are observed,which is caused by the central segregation of the strand and also indicate that these defects have no noticeable effect on the strength,low temperature impact toughness and bending property of the plate.The main factor leading to the macroscopic corrosion cracking is caused by the fine strip inclusion MnS formed in the segregation band at the central pearlite of the plate,and the plate has no any cracking defects.