基于热模拟试验的双相钢盘条热轧工艺设计

Design of Hot Rolling Process Based on Thermal Simulating Experiments for Producing Wire Rod With Dual Phase Microstructure

采用Gleeble 1500热模拟试验机模拟了ER70S-6钢在高速线材生产中的精轧和冷却工艺,并根据模拟试验结果绘制了ER70S-6钢的动态CCT曲线图,优化了获得双相组织的精轧和冷却工艺。结果表明,在845℃变形后以大于10℃/s冷速冷却,ER70S-6钢可以获得含约11%马氏体的双相组织;冷速大于30℃/s时变形组织的晶粒尺寸较小,约4.2μm。变形后以大于30℃/s的冷速冷却,ER70S-6钢可以获得晶粒尺寸细小、马氏体含量稳定的双相组织。通过热模拟试验的指导,在高速线材轧机上成功生产出晶粒尺寸约8.2μm、马氏体含量约11.5%的双相组织盘条。

The finishing rolling and controlling cooling processes of ER70S-6 steel production in high-speed wire rolling mill were simulated by Gleeble 1500 simulator,then the dynamic CCT curves of the steel was plotted,and the finishing rolling and controlling cooling processes for obtaining dual phase microstructure were optimized.The results show that after deformation at the temperature of 845 ℃ and cooling at a rate of higher than 10 ℃/s ER70S-6 steel has a dual phase microstructure with about 11% martensite in volume fraction.After cooling at a rate of higher than 30 ℃/s the deformed microstructure has a finer grain size of about 4.2 μm.In general,after deformation and cooling at a rate of higher than 30 ℃/s,a dual phase microstructure with fine grain size and constant volume of martensite can be obtained for ER70S-6 steel.Guided by the thermal simulating experiments,the wire rod with a dual phase microstructure of 8.2 μm in grain size and 11.5% in martensitic volume fraction has been produced successfully in high-speed wire rolling mill.