Effects of temperature on the friction-wear properties of 40Cr steel by warm extrusion
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摘要: 采用溫擠壓技術對40Cr鋼進行成形試驗，考察了不同溫度下溫擠壓試樣的摩擦-磨損行為.通過掃描電鏡、能譜儀和X射線衍射儀分析了40Cr鋼磨損后表面形貌、化學元素分布和物相組成，討論了40Cr鋼溫擠壓的磨損機理.結果表明，在擠壓溫度為550℃時試樣晶粒尺寸細小，殘余奧氏體含量較高，硬度最高，其磨損性能為最佳；而當溫度為650℃和750℃時，晶粒尺寸較粗大，殘余奧氏體含量降低.在5N載荷作用下，擠壓溫度為550℃時，摩擦因數為0.7667；當擠壓溫度達到650℃，摩擦因數為0.8587，提高了12.01%，磨損性能降低；750℃時，摩擦因數為0.8764，相比550℃提高了14.31%，磨損性能進一步變差；在550、650和750℃時，磨損形式主要為磨粒磨損.Abstract: A forming experiment of 40Cr steel was conducted by using a warm extrusion technology, and the friction-wear behavior of the samples at different extrusion temperatures were observed. The wear morphologies, distributions of chemical elements and phase compositions were analyzed by scanning electronic microscopy (SEM), energy diffusive spectrometry (EDS), and X-ray diffraction (XRD), respectively, and the wear mechanism of warm extrusion on 40Cr steel was discussed. The results show that the grains are samll by warm extrusion at 550℃, the content of retained austenite is higher, and the hardness is the highest, showing that the wear resistance is the best. The size of grains is bigger and the contents of retained austenite decrease at the extrusion temperature of 650℃ and 750℃. The coefficient of friction is 0.7667 at the extrusion temperature of 550℃ under the load of 5 N, while that is 0.8587 at the extrusion temperatures of 650℃, which increases by 12.01%, and the wear performance decreases. At the extrusion temperature of 750℃, the coefficient of friction is 0.8764, which increases by 14.31% compared with 550℃, and the wear performance is worse. The wear forms of the samples at 550, 650 and 750℃ are common abrasive wear.
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Key words:
- warm extrusion /
- alloy steel /
- extrusion temperature /
- wear performance
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參考文獻
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