A plastic strain energy method exploration between machined surface integrity evolution and torsion fatigue behaviour of low alloy steel

• Published in: Chinese journal of aeronautics Vol. 35; no. 10; pp. 412 - 429
• Main Authors: WANG, Yong, WANG, Xibin, LIU, Zhibing, LIU, Shuyao, WANG, Sitao, CHEN, Hongtao, SONG, Ci, BAI, Yifan, WANG, Pai, LIU, Yang
• Format: Journal Article
• Language: English
• Published: School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China%Key Laboratory of Fundamental Science for Advanced Machining,Beijing Institute of Technology,Beijing 100081,China%Beijing North Vehicle Group Corporation,Beijing 100072,China 01.10.2022
• Subjects: Cyclic hysteresis loop; Torsional fatigue; Strain energy; Surface integrity evolution; Multistage machining pro-cesses
• ISSN: 1000-9361
• DOI: 10.1016/j.cja.2021.11.003

To explore the evolution mechanism of multistage machining processes and torsional fatigue behaviour based on strain energy for the first time and provide process optimization of axis parts of low alloy steel for service performance,four multistage machining processes were applied to the 45CrNiMoVA steel,including the Rough Turning process(RT),RT+the Finish Turning pro-cess(FRT),FRT+the Grinding process(GFRT)and RT+the Finish Turning process on dry cut-ting condition(FRT0).The result showed that the FRT process's average low-cycle torsional fatigue life increased by 50％when it evolved from the RT process.The lower surface roughness of Ra 1.3 μm caused the total strain energy to increase by 163.8 Pa mm/mm instead of the unchanged strain energy density,and the crack feature evolved from some specific bulges to flat shear plane characteristics.When the GFRT process evolved from the FRT process,its average fatigue life increased by 1.45 times,compared with the RT process.Plastic strain amplitude decreased by 21％,and the strain energy density decreased by 4％due to more considerable com-pressive residual stress(-249 MPa).Plastic deformation layer depth had a consistent tendency with surface roughness.In this paper,surface integrity evolutions on cyclic characteristics and fatigue behaviour have also been explained.A fatigue life prediction model based on the energy method for machined surface integrity is proposed.