45钢块体超细晶棒材3D-SPD轧制法  

3D-SPD Rolling Method of 45 Steel Ultrafine Grained Bar with Bulk Size

作　　者：林鹏程 庞玉华[1,2] 孙琦 王航舵[1,2] 刘东 张喆 LIN Pengcheng;PANG Yuhua;SUN Qi;WANG Hangduo;LIU Dong;ZHANG Zhe(School of Metallurgical Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China;Shaanxi Metallurgical Engineering Technology Research Center,Xi'an University of Architecture and Technology,Xi'an 710055,China;School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西安建筑科技大学冶金工程学院,西安710055 [2]西安建筑科技大学陕西省冶金工程技术研究中心,西安710055 [3]西北工业大学材料学院,西安710072

出　　处：《金属学报》2021年第5期605-612,共8页Acta Metallurgica Sinica

基　　金：陕西省重点研发计划项目No.2020GY-253。

摘　　要：提出了一种基于斜轧原理的块体超细晶棒材剧烈塑性变形(SPD)成形法,称为3D-SPD法:利用特殊曲面锥形轧辊及导板,坯料从轧辊直径最大端咬入,采用超大送进角及径缩率等变形参数,构建了剧烈扭转压缩复合变形区,单位成形载荷为兆帕级,可实现块体等效应变大于6.5的SPD。建立了基于Oyane损伤准则的裂纹萌生控制模型,通过对不同变形条件下轧件心部损伤值的优化,有效抑制了Mannesmann效应(ME),避免了裂纹的萌生。理论及实验证明:当辊面锥角5°、送进角24°、径缩率50%、温度700℃、椭圆度系数1.02以及轧辊转速40 r/min时,采用单道次轧制方式,可将直径50 mm的45钢轧制为直径25 mm的超细晶棒材,平均晶粒尺寸从46μm细化至约1μm,屈服强度和抗拉强度分别提升46%和42%。Based on the limitations of severe plastic deformation(SPD) technology, such as a small effective deformation area and huge forming load, in the preparation of ultrafine grained/nanocrystalline materials, preparing industrial grade bulk ultrafine grained materials is difficult. In this work, a new SPD method, titled 3 D-SPD, for preparing bulk ultrafine grained bars is proposed based on the cross-rolling principle. A severe torsion and compression deformation region was constructed using specially-curved conical rolls and guide plates, super large feed angles, and diameter reduction ratios. During the 3 D-SPD process, a billet entered the deformation region from the large diameter side of the roll, where the deformation pressure was MPa grade and able to realize the SPD process with effective strains greater than 6.5. A crack control model based on Oyane criteria was established. Through the optimization analysis of damage factors under different deformation conditions, the crack induced by the Mannesmann effect was effectively restrained. Based on theoretical and experimental results, optimal parameters were determined as follows: cone angle 5°, feed angle 24°, diameter reduction ratio 50%, temperature 700 oC, ovality coefficient 1.02, and roll speed 40 r/min. A 25 mm-diameter ultrafine grained bar of 45 steel was obtained by the single pass deformation. The average grain size was refined from 46 μm to 1 μm, and the yield and tensile strengths were increased by 46% and 42%, respectively.

关 键 词：剧烈塑性变形 超细晶棒材 3D-SPD Mannesmann效应 剧烈扭转压缩复合变形区 

分 类 号：TG146.23[一般工业技术—材料科学与工程]