| SUN Yu-feng,ZUO Peng-peng,JI Jie,WU Xiao-chun.Effect of Nitriding Time and Roughness on High Temperature Wear Property of Plasma Nitriding 4Cr5Mo2V Steel[J],50(4):198-204, 234 |
| Effect of Nitriding Time and Roughness on High Temperature Wear Property of Plasma Nitriding 4Cr5Mo2V Steel |
| Received:April 09, 2020 Revised:May 27, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.04.019 |
| KeyWord:4Cr5Mo2V steel roughness plasma nitriding microstructure porosity high temperature friction and wear property |
| Author | Institution |
| SUN Yu-feng |
School of Materials Science and Engineering, Shanghai University, Shanghai , China |
| ZUO Peng-peng |
School of Materials Science and Engineering, Shanghai University, Shanghai , China |
| JI Jie |
School of Materials Science and Engineering, Shanghai University, Shanghai , China |
| WU Xiao-chun |
School of Materials Science and Engineering, Shanghai University, Shanghai , China |
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| Abstract: |
| To improve the high temperature wear performance of plasma nitriding layer of 4Cr5Mo2V steel, in this paper, the plasma nitriding of 4Cr5Mo2V steel was carried out by orthogonal and single variable experiments with surface roughness and nitriding time as variables. The surface hardness, microhardness gradient, effective thickness, porosity, phase and high temperature wear properties of plasma nitriding layer of 4Cr5Mo2V steel were characterized by microhardness test, optical microscope observation, X-ray diffraction (XRD) and high temperature friction and wear test. Scanning electron microscope (SEM) and optical profilometer were used to analyze the microstructure of the infiltration layer, the wear volume of the high temperature friction and wear samples, the wear trace morphology and the section morphology. The results showed that when nitriding time was 6 h, the surface hardness and effective thickness of the layer increased with the increase of roughness, but when the porosity was 3-4 grade, the quality of the layer was poor and the wear performance at high temperature was bad; when the nitriding time was more than 10 hours, the effect of plasma nitriding was the opposite, and the nitriding layer of the sample with roughness of 1.05 μm gradually thinned to 200 μm, and the porosity of the nitriding layer further increased to level 5; when the nitriding time reached 14 h, the sample with roughness of 0.15 μm got the best nitriding layer. The effective thickness of the infiltrated layer was 300 μm, the microhardness gradient was level 5, and the porosity of the infiltrated layer was level 1. At this time, the wear rate was 64% lower than that of the nitriding sample with the roughness of 1.05 μm under the high temperature friction and wear test. The high temperature wear performance was significantly improved. With the increase of nitriding time, enlarged surface roughness will cause the plasma nitriding layer of 4Cr5Mo2V steel to thin and its porosity to increase, and its high temperature wear performance is poor. The plasma nitriding layer of 4Cr5Mo2V steel with surface roughness of 0.15 μm has the best quality after 14 h nitriding, which can effectively improve the high temperature wear performance of the layer. |
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