SWRH82B盘条拉拔横裂纹分析

Transverse crack analysis of SWRH 82B wire rod drawing

用于制作预应力钢绞线的SWRH82BΦ13 mm盘条拉拔到Φ5.02 mm时产生横向裂纹。采用扫描电镜、大型金相显微镜对拉拔横裂纹试样进行观察并分析,结果表明:造成横裂纹的原因之一是盘条表面增碳。碳富集较轻部位出现网状渗碳体,局部碳富集区严重的出现莱氏体。通过采取结晶器和末端电磁搅拌,自动液面控制技术,防止浇注时卷渣,配合低过热度浇注、恒速浇注、合理比水量可消除表面增碳。

Transverse crack was produced while SWRH82B diameter 13 mm wire rod for producing prestressed steel strand was deep drawing to 05.02 ram. The drawing transverse crack sample was observed and analyzed by using SEM, large metallographic microscope. Results show that one of the reasons causing transverse crack is recarburization in wire rod surface. Network cementite appears in slight carbon concentration area. Ledeburite appears in serious local carbon concentration area. By using crystallizer and final electromagnetic stirring, automatic liquid level control technology, to prevent slag entrapment while casting, to match low superheat casting, constant speed casting, rational water rate, the surface recarburization can be eliminated.