| LIU Zhi-hua,ZHANG Tian-zeng,YANG Meng-jian,ZHANG Yin-xia,WANG Dong.Effect of Ultrasonic Rolling Parameters on Surface Properties of 18CrNiMo7-6 Gear Steel[J],49(3):309-318 |
| Effect of Ultrasonic Rolling Parameters on Surface Properties of 18CrNiMo7-6 Gear Steel |
| Received:May 12, 2019 Revised:March 20, 2020 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2020.03.039 |
| KeyWord:ultrasonic rolling process gear steel analytical model surface roughness microhardness compressive residual stress surface quality |
| Author | Institution |
| LIU Zhi-hua |
School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou , China |
| ZHANG Tian-zeng |
School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou , China |
| YANG Meng-jian |
School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou , China |
| ZHANG Yin-xia |
School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou , China |
| WANG Dong |
School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou , China |
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| Abstract: |
| The paper aims to study the effects of different ultrasonic rolling parameters on the surface quality of 18CrNiMo7-6 gear steel and its significance sequence. It also aims to establish an analytical model of surface roughness to research the influences of feed rate, repeat processing numbers and initial surface roughness on surface quality and compare them with the experimental results. The specimen was clamped on the blade adapter. The end face of 18CrNiMo7-6 gear steel rod material was turned first, and then processed by ultrasonic rolling. The surface roughness, surface microhardness, surface two-dimensional morphology and surface residual stress were measured by special equipment such as three-dimensional topography measuring instrument. Then orthogonal experiment was carried out to find the factors of significant effect on the surface roughness of the sample. An analytical model of surface roughness was established, and the analytical model data were compared with the experimental data to obtain the influence of ultrasonic rolling process on surface roughness, surface two dimensional morphology of ultrasonic rolling, surface microhardness and surface residual stress. The order and significance of the effect of ultrasonic rolling process parameters on surface roughness was: feed rate, spindle speed, repeat processing numbers, vibration amplitude, static pressure; and the analytical model of surface roughness can better predict the surface roughness after ultrasonic rolling. The calculated theoretical data was very close to the experimental data; after ultrasonic rolling, the surface roughness of the sample was reduced from the turned Ra 3.003 μm to Ra 0.468 μm. The obvious work hardening was obtained on the surface layer of the gear steel, and its depth was about 260 μm; the surface microhardness was increased from 360.9HV to 417.6HV, increased by 15.7%. A spoon-shaped residual stress was formed in the surface layer. The maximum compressive residual stress, which was about –790.97 MPa, appeared in the depth of 60 μm from the machined surface and the compressive residual stress layer reached 800 μm. As a result, ultrasonic rolling process can remarkably improve the surface performance of 18CrNiMo7-6 gear steel specimen, and the feed rate is the most significant factor. |
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