CSP生产700MPa级高强钢板卷氧化层分布规律

Oxide scale distribution on 700 MPa grade high strength steel coils rolled by CSP process

对CSP生产的700 MPa级高强钢板卷上表面氧化层进行了研究.发现钢卷沿卷长方向头部、中部氧化层主要由Fe+Fe3O4共析组织构成,而尾部则主要由Fe2O3层和Fe3O4层双层组织构成.沿板宽方向,边部的氧化层较厚,离边部越远,氧化层越薄.从边部到板宽中心,Fe2O3层和Fe3O4层的比例逐渐减少,Fe+Fe3O4共析组织逐渐增加,到距边部300 mm时氧化层几乎全部由Fe+Fe3O4共析组织构成.相较于CSP生产的SPHC钢,前者氧化层厚度对板卷厚度变化不太敏感.

Oxide scales on the surface of 700 MPa grade high strength steel produced by CSP process were studied in this paper. It is found that along the length direction of the coil, the oxide scales on the head and the middle mostly consist of magnetite-iron eutectoid, but the oxide scale on the tail is a double-layered structure with the outer layer of Fe203 and the inner layer of Fe3Oa. Along the width direction of the coil, the oxide scale is thick at the edge, and it thins as far away from the edge. The percentage of Fe203 and Fe3Oa phase decreases and the proportion of magnetite-iron eutectoid increases from the edge to the width center. When the distance is over 300 mm apart from the edge the oxide scale entirely consists of magnetite-iron eutectoid. In comparison with SPHC steel produced by CSP, the oxide scale thickness of 700 MPa grade high strength steel produced by CSP is less sensitive to strip thickness.