高强度船板拉伸断口分层原因分析

针对高强度船板拉伸试样断口出现分层的问题,对典型断口分层试样和断口合格试样取样进行金相检验及扫描电镜能谱分析,结果表明,异常断口试样夹杂物级别高,试样心部组织晶粒粗大,带状组织明显且有裂纹,分析认为,2.0级以上的硅酸盐夹杂和MnS夹杂、28μm宽的珠光体带及Ti、Nb元素的富集是导致拉伸裂纹进而出现断口分层的主要原因。

Reason Analysis of Layered Fracture of High Strength Ship Plate Sample after Tension Test

Because layered fracture appeared in the tension samples of high-strength steel plate for ships, the simples with typical layered fracture and regular fracture were sampled separately for metallographic examination and SEM and EDAX analyses. The results showed that the level of the inclusions in the sample with abnormal fracture is high, the structure grains in the sample core are coarse and the banded structure with cracks is obvious. Analyses consider that: the silicate inclusions more than 2.0 grade and MnS, the pearlite band with 28μm width and the Ti and Ni enrichment are main reasons resulted in tension cracks and layered fracture.