Q235C厚规格钢板折弯开裂的原因分析

Analysis of the Causes of Thick Steel Plate Bending Cracking Q235C

针对复合坯轧制厚度100 mm的Q235C钢板折弯开裂原因进行了分析。通过对试样进行夹杂物、成分和低倍分析,发现铸坯[O]含量偏高,成分偏析较大,低倍偏析严重。由于铸坯内部质量差,轧制后内部存在微裂纹,使用过程中应力不均,裂纹进一步扩展,加之厚度较大,最终导致钢板折弯开裂。通过控制合适的过热度,提高铸坯内部质量,避免成分偏差较大的钢种进行连浇生产,可以防止厚规格钢板折弯开裂。

By analyzing the inclusions, components and macrostructure of the specimen, it was found that the [0] content of the casting was higher, the segregation on chemical composition and maerostructure were severe. Due to poor internal quality of casting billet, there exist internal micro cracks after rolling, and there is the uneven stress in the application, the crack can be further developed, combined with the bigger thickness, the bending crack is the final result for the steel plate. By controlling the appropriate degree of superheat, internal quality of slab can be improved. By avoiding casting production between different composition of steel, the bending crack can be prevented for the thick steel plates.