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Modeling and analysis of tangential force in robot abrasive belt grinding of nickel‑based superalloy

Zhang Weijian, Gong Yadong, Zhao Xianli, Xu Yunchao, Li Xiang, Yin Guoqiang, Zhao Jibin

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e124, 2023

EN

Grinding force directly affects the grinding equipment performance, the grinding tool wear, and the machined surface quality, and it is an important grinding performance indicator. In this paper, a tangential force prediction model is established for robot abrasive belt grinding (RABG) of nickel-based superalloy. According to the shape characteristics of grits and the interaction mechanism between grits and workpiece, the tangential components of cutting force and frictional force on the grits are determined. On this basis, the tangential force prediction model is established by the grit protrusion height distribution and the elastic contact theory. In addition, according to the wear characteristics of the structured abrasive belt, the expression of grit distribution density (i.e. the number of grits per unit area) is obtained and applied to the tangential force model. The force model is evaluated by the verification experiment, and the results show that it has good prediction ability. At the same time, this paper discusses the influence of grinding parameters on tangential force, and reveals the material removal characteristics of RABG of nickel-based superalloy based on the analysis of the tangential force and the morphology characteristics of grinding surfaces and chips.

2

Effect of grinding conditions on the friction and wear performance of Ni based singlecrystal superalloy

Xu Yunchao, Gong Yadong, Zhang Weiqiang, Wen Xuelong, Xin Bo, Zhang Huan

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e102, 1--16

EN

In this work, four types of surfaces were prepared as follows: untreated one, dry grinding (DG), wet grinding (WG) and minimum quantity lubrication grinding (MQLG) for Ni-based single crystal superalloy. The effects of grinding conditions on the surface roughness and microstructure evolution were studied. Dry sliding tests of ground surfaces were carried out at room temperature. Through the quantitative characterization of the wear rate, the area, width and depth of the worn profiles, the friction and wear mechanism of superalloy prepared by different grinding conditions were analyzed. The results show that the MQLG surface with low surface roughness and work hardening behavior has the best wear resistance. The element transfer behavior from the GCr15 ball to the worn surface was detected by EDS analysis. The wear type is mainly abrasive wear, accompanied by slight adhesive wear and oxidation wear. It is shown that high-quality surface with nanocrystalline and high density dislocation structure produced by MQLG improves the tribological properties of superalloy, which provide theoretical guidance for the surface machining of single crystal blade to reduce fretting wear.

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Experimental study of Ni-based single-crystal superalloy: Microstructure evolution and work hardening of ground subsurface

Xu Yunchao, Gong Yadong, Wang Zhongxu, Wen Xuelong, Yin Guoqiang, Zhang Huan, Qi Yang

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

74--84

EN

In the present study, the grinding experiment of second-generation nickel-based single-crystal superalloy DD5 was carried out under different grinding parameters. The grinding force was recorded during the grinding process, and it was found that it decreased with increasing grinding speed and increased with feed speed. The microstructure evolution of ground subsurface was obtained by optical microscope (OM) and scanning electron microscope (SEM), and the elemental distribution of γ/γ' phases was investigated by energy dispersion spectrum (EDS). The results show that there are two layers different from the bulk material beneath the ground surface: (i) a white layer (WL) with no obvious structural features under limited observation scale and (ii) a severe deformed layer (SDL) with the elongated and rotated γ' phase and the narrowed γ channel. Elements segregation behavior exists in both the white layer and severe deformed layer. The grinding parameters have a great influence on the thickness of the white layer, which is due to the elemental diffusion behavior caused by intensive thermo-mechanical load. There is work hardening in the white layer, and the hardening degree aggravates with the increase in cutting speed and feed speed.

4

Inconel-steel functionally bimetal materials by hybrid directed energy deposition and thermal milling: Microstructure and mechanical properties

Li Pengfei, Gong Yadong, Xu Yunchao, Qi Yang, Sun Yao, Zhang Huan

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 3

820--831

EN

Many engineering applications, particularly those in extreme environments, require com-ponents with properties that vary with location in the part. Functionally bimetal materials (FBM) that combine dissimilar materials, such as those with different density and thermal properties, provide a potential solution to this need. Directed energy deposition (DED) is convenient to fabricate all kinds of complicated parts and to clad different materials at specific locations. Milling can improve the surface quality and dimensional accuracy after DED. Hybrid DED and thermal milling manufacturing can fabricate FBMs and be applied to laser repair. This study used this new method to fabricate Inconel-steel FBM. Inconel 718 powder and 316L stainless steel powder were deposited on the thermal milling surface of parts prepared with DED. The interfacial characteristics of different cladding materials were compared. Microstructure, chemistry, phase composition, element segregation and micro-hardness varied with position and were characterized by energy dispersive spectroscopy, X-ray diffraction, scanning electron microscopy and microhardness testing. Finally, the tensile properties of the FBM were compared to other materials, and the fracture location and morphology were analyzed. The results showed that the yield strength (YS) reached 368 MPa, and the ultimate tensile strength (UTS) reached 516 MPa. The Vickers microhard-ness of the diffusion layer was approximately 250 HV.