含磷高强钢板拉矫破鳞过程的氧化皮剥离机理  

Oxide scale peeling mechanism of high strength steel sheets containing phosphorus during descaling process

作　　者：孔宁[1] 杨迪 张杰[1] 李洪波[1] 王一博 KONG Ning;YANG Di;ZHANG Jie;LI Hong-bo;WANG Yi-bo(School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学机械工程学院,北京100083

出　　处：《钢铁》2021年第1期59-68,共10页Iron and Steel

基　　金：国家自然科学基金资助项目(51605026);中央高校基本科研业务费专项资金资助项目(FRF-TP-15-082A1)。

摘　　要：为提升含磷高强钢板的拉矫破鳞效率,采用弯曲试验模拟拉矫过程中超低碳含磷高强钢板表面氧化铁皮的剥离过程,并以中点位置的压下量表征拉矫机弯曲辊的插入深度。通过表面微观检测可知,附着于带钢基体上的氧化铁皮在压应力下呈现块状剥离,拉应力下则主要表现为裂纹扩展。同时,采用ImageJ开源图像识别软件进行氧化铁皮剥离率及破裂度统计计算,发现两种应力状态下的带钢表面氧化铁皮剥离率及破裂度随着压下量的增加都趋于饱和,但饱和点却有较大差异。由于残余压应力的存在、内外侧表面应力状态及带钢基底与氧化铁皮材料属性的差异,导致氧化铁皮在带钢两侧的剥离形式截然不同。采用MARC有限元软件仿真了插入深度对拉矫伸长率的影响,并结合弯曲试验及微观分析结果可知,伸长率并不能完全表征破鳞效果,需要结合应力状态来综合评价。The bending tests were used to simulate the peeling process of oxide scale on the surface of ultra-low carbon high strength steel sheets containing phosphorus in order to improve its descaling efficiency.The reduction on the middle of the strip was changed in the bending tests in order to study the insertion depth of the bending roll on the withdrawal and straightening leveler.The oxide scale attached to the strip substrate appears as massive exfoliation under the compressive stress,while it mainly shows as crack propagation under the tensile stress condition.An open-source image recognition software,ImageJ,was applied to evaluate the peeling rate and fracturing rate.The results show that the peeling rate of the oxide scale increases with the compressive stress,while the fracturing rate increases with the tensile stress.But both the peeling rate and fracturing rate tend to be a saturation point with the stress increase and the saturation points are quite different.The spalling form of the oxide scale between both strip sides is various due to the existence of residual stress,the different stress state between inner and outer strip surface,and the various material properties of the strip substrate and its oxide scale.The finite element software MARC was conducted to study the effect of insertion depth on the elongation of the withdrawal and straightening leveler.The results from bending tests,microscopic analysis,and simulation conclude that only the elongation cannot fully reflect the descaling effect.The stress state of the oxide scale on the strip surface is also a key factor to evaluate the descaling efficiency.

关 键 词：拉矫破鳞 剥离率 破裂度 应力状态 力学仿真 

分 类 号：TG335[金属学及工艺—金属压力加工]