冷拉拔对Nb微合金化桥梁缆索用钢丝显微组织和力学性能的影响  

Effect of cold drawing on microstructure and mechanical properties of Nb microalloyed steel wire for bridge cable

作　　者：贾力 胡丞杨 朱晓雄 成林[1] 赵军 吴开明[1] JIA Li;HU Chengyang;ZHU Xiaoxiong;CCHENG Lin;ZHAO Jun;WU Kaiming(Collaborative Innovation Center for Advanced Steels,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Jiangsu Tokyo Rope Co.,Ltd.,Fasten Group,Wuxi 214445,Jiangsu,China)

机构地区：[1]武汉科技大学高性能钢铁材料及其应用省部共建协同创新中心,湖北武汉430081 [2]法尔胜泓昇集团有限公司江苏东纲金属制品有限公司,江苏无锡214445

出　　处：《钢铁研究学报》2024年第7期947-956,共10页Journal of Iron and Steel Research

基　　金：国家重点研发计划资助项目(2022YFB3706701);中国博士后科学基金资助项目(2023M730592);111计划资助项目(D18018)。

摘　　要：钢中加入Nb元素可以起到析出强化和细晶强化的作用,而利用冷拉拔可以改善钢丝的显微组织,从而优化钢丝的综合性能。为了研究冷拉拔对Nb微合金化后的钢丝组织和性能的影响,利用扭转试验机和慢应变拉伸机分别对比了扭转性能和不同冷拉拔应变量钢丝的抗拉强度,同时利用扫描电子显微镜(SEM)和透射电镜(TEM)对不同应变量钢丝的显微组织和断口形貌进行观察分析,运用背散射衍射(EBSD)技术对显微组织亚结构进行分析。结果表明,冷拉拔会显著提高Nb微合金化桥梁缆索用钢丝的屈服强度和抗拉强度,略微降低其塑性。冷拉拔过程中物理压缩和珠光体片层间的相互作用导致了钢丝的片层弯折卷曲,并向拉拔方向旋转,其中一些较大团簇会破碎,最终实现晶粒细化。与此同时,微观残余应力的积累导致大量位错缠结形成位错胞。强化机制分析表明,位错胞的减小导致了钢丝强度的增加和塑性的降低。同时,拉拔过程产生的残余应力也会造成钢丝断口处裂纹的拓展,经过去应力处理后,会提升钢丝扭转性能并延缓钢丝的裂纹拓展。Utilizing Nb microalloying in steel can enhance precipitation strengthening and grain refinement strengthening.Additionally,employing cold drawing techniques can improve the microstructure and mechanical properties of steel wire,thereby optimizing its comprehensive performance.In order to study the effect of cold drawing on the properties of Nb microalloyed steel wires,the torsional properties and tensile strength of steel wires with different cold drawn strains were compared using torsional testing machines and slow strain tensile machines.Additionally,the microstructure and fracture morphology of steel wires with varying strain rates were examined and analyzed by using scanning electron microscope(SEM),electron backscatter diffraction(EBSD)and transmission electron microscope(TEM).The findings demonstrate that cold drawing substantially enhances the yield strength and tensile strength of high-strength pearlite steel,albeit with a minor decrease in its plasticity.During the cold drawing process,the pearlite lamellae of steel wire undergo bending,curling,and rotating to the drawing direction due to physical compression and interaction between the lamellae.This process also leads to the breaking of larger clusters,resulting in grain refinement.Simultaneously,the augmentation of remaining tensile stress resulted in a significant accumulation of dislocation entanglements and the formation of dislocation cells.The analysis of the strengthening mechanism demonstrates that the decrease in dislocation cells leads to an increment in the strength of the steel wire and a reduction in its plasticity.Additionally,the residual stress induced during the cold drawing process can lead to the expansion of cracks on the fracture surface of the steel wire.However,by stress releasing treatment,the torsional performance and crack propagation of the steel wire can beenhanced.

关 键 词：冷拉拔 应变量 珠光体钢 组织 力学性能 

分 类 号：TG356.11[金属学及工艺—金属压力加工]