低合金冷轧高强钢HC340LA工艺优化生产实践

OPTIMIZATION PRODUCTION PRACTICE OF LOW ALLOY COLD ROLLED HIGH STRENGTH STEEL HC340LA PROCESS

为解决HC340LA存在的屈服强度波动大且性能合格率低的问题,窄成分控制钢中的主要强化元素C、Mn、Nb,提高0.40~0.79 mm规格的卷取温度、退火温度,并适当降低运行带速,降低1.60~2.00 mm规格的卷取温度、退火温度,并适当提高运行带速,减少了屈服强度波动,使力学性能合格率得到了明显提升。统计了优化后正常生产的HC340LA的力学性能,屈服强度平均从375 MPa降低至364 MPa,波动范围从82 MPa降低至30 MPa,抗拉强度平均从483 MPa降低至476 MPa,伸长率平均在28%以上,力学性能合格率从98.8%提升至99.8%。

In order to solve the problem of large yield strength fluctuations and low performance qualification rate in HC340LA,the main strengthening elements C,Mn,and Nb in the narrow composition control steel are increased by increasing the coiling temperature and annealing temperature of thin specifications,appropriately reducing the operating belt speed,lowering the coiling temperature and annealing temperature of thick specifications,and appropriately increasing the operating belt speed,reducing yield strength fluctuations,and significantly improving the mechanical performance qualification rate.After optimization,the mechanical properties of HC340LA in normal production were statistically analyzed.The average yield strength decreased from 375 MPa to 364 MPa,the fluctuation range decreased from 82 MPa to 30 MPa,the average tensile strength decreased from 483 MPa to 476 MPa,the average elongation was above 28%,and the mechanical property qualification rate increased from 98.8%to 99.8%.