超高强度船板E47性能不合原因分析与控制

Disqualifications analysis and control on E47 extra high strength ship steel plate

利用金相显微镜对不合格的E47船板试样进行金相组织观察,金相显示,贝氏体仅在试样厚度方向中心位置存在,而未形成所需的全断面贝氏体,这是导致性能不合格的根本原因。试样表层金相组织为珠光体＋铁素体,其形成所需的冷速较贝氏体慢,这与现场实际生产工艺控制不符。结合金相组织分析和轧制过程情况,对轧制工艺进行摸索和优化,最终获得了全断面贝氏体组织,解决了E47船用钢板强度值不合格的问题,满足了船级社的相关标准要求。

The microstructure of the disqualified E47 ship steel plate sample are analyzed by metallographic microscrope. The bainite are in the center along thickness direction,not all over the section,this is the main reason for performance disqualification. On the surface of the samples there are ferrite and pearlite which formed in the lower cooling rate. This is different from the actual production control process. Based on microstructure analysis and the rolling technology,improving the rolling process,the bainite structure on whole section of the plate are obtained,and the disqualifications of the strength are solved,and the results meet the requirements of the classification society.