磷的表面逆偏析对铸轧低碳钢力学性能的影响

Effects of Inversed Surface Segregation of Phosphorus in Twin Roll Cast Strips on Mechanical Properties of Low Carbon Steel

通过组织分析探讨了铸轧薄带中磷的表面逆偏析的形成,通过力学性能测试研究了磷的表面逆偏析对铸轧低碳钢力学性能的影响.结果表明,铸轧薄带经冷轧和退火处理后磷在薄带表面形成一均匀的富磷层,当磷质量分数超过0.15%时,常规薄带的延伸率开始急剧下降,而磷质量分数为0.26%的铸轧薄带的延伸率保持在30%左右,即铸轧工艺能够将带钢的容磷能力提高大约0.1%;铸轧薄带韧脆转变温度(DBTT)均比相同磷含量的常规薄带低.

How the inversed surface segregation of P forms in strip casting was discussed by structure observing and analyzing,and its effects on the mechanical properties of twin roll cast strips were investigated through tests.The results showed that a homogeneous P-rich surface layer forms on the strip after cold rolling and annealing.The percentage elongation of conventional strips will drastically decrease if P content is over 0.15%,but it will be kept to about 30% if P content is 0.26%.It means that the twin roll strip casting process can raise the P tolerance in strip by about 0.1%.In addition,the ductile-brittle transition temperature （DBTT） of the cast strips is lower than that of conventional strips though the P content is the same.