磷的表面逆偏析对铸轧薄带钢耐候性能的影响

Effect of Surface Inversed Segregation of Phosphorus on Weathering Resistance Property of Cast Strip Steel

采用双辊薄带铸轧机制备出P含量高达0.15 mass%(下同)的高P耐候钢薄带,发现磷偏析于薄带表面,经冷轧和退火处理后在薄带表面形成一均匀的富P层.通过实验室加速腐蚀试验研究了磷的表面逆偏析对高P薄带耐候性能的影响.结果表明,在120周期的加速腐蚀后,与P含量为0.080%的常规耐候钢相比,高P薄带锈层增重量减少31%;在高P薄带的锈层和基体之间形成了致密的腐蚀阻挡层,降低了腐蚀速度,提高了薄带的耐候性能.

Cast strip containing 0.15 mass% P was made by using a pilot twin-roll strip caster.It was found that P was segregated towards the strip surface.A uniform surface layer enriched in P may formed on the steel strip after subsequent processing of cold rolling and annealing.The effect of surface inversed segregation of P on weathering resistance property of high-P strip was investigated by accelerated corrosion test,a wet-dry cyclic test simulated industrial atmosphere corrosion.The test results for 120 cycles each cycle lasts 12 h indicated that the weight gain of the high-P strip was reduced by 31% as compared with that of the conventional weathering resistant strip containing 0.08% P and that a dense barrier layer was formed beneath the corrosion scale of the cast strip after cold rolling and annealing,which reduced the corrosion rate and enhanced the weathering resistance of the steel strip.