摘要
针对国内某钢厂采用Nb微合金化和控冷工艺生产HRB500高强度抗震钢筋出现的伸长率偏低情况,取样进行了金相显微组织、断口形貌、夹杂物及化学成分分析研究。结果表明,HRB500钢筋伸长率偏低的主要原因是钢筋心部显微组织异常,贝氏体含量高(50%)且形态差(大块状),原始奥氏体晶粒粗大(50～60μm);显微组织异常的主要原因是轧钢加热温度高(1260℃)、控冷后终止温度偏低(710℃)。针对上述情况,炼钢采取了渣洗工艺、延长吹氩时间(长于200s)、严格控制中包浇铸液面(大于650mm)的措施,轧钢采取了降低加热温度(均热段温度低于1200℃)、升高控冷后终止温度(高于725℃)的措施,HRB500钢筋伸长率偏低得到消除。
In view of lower elongation of HRB500 high-strength and anti-seismic rebars with Nb-microalloying and controlled cooling process in domestic steel plant, microstrueture, morphology of fracture, inclusions, chemical composition by sampling are analyzed and researched. The results show that main reason of lower elongation of HRB500 rebars is emergence of abnormal center microstructure for rebars, appearance of high content（50%） and bad morphology（big block） of bainite, the original austenite grain is coarse（50-60μm） ; the main reason of abnormal microstrueture for rebars is that steel-rolling heating temperature is higher（1260℃）, termination temperature after con-trolled cooling is lower（710℃ ）. In view of aboved reason, slag rinsing process, extending the time of blowing argon （longer than 200s）, strict control of casting liquid level hight （higher than 650mm） are carried out in steel-making,meanwhile, reducing heating temperature, increasing termination temperature after controlled cooling are carried out in steel-rolling, the lower elongation of HRB500 rebars is eliminated.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2010年第14期56-59,共4页
Materials Reports
基金
云南省科技计划项目(2009BA008)
关键词
HRB500
伸长率
贝氏体
加热温度
终止温度
HRB500, elongation, bainite, heating temperature, termination temperature
