【目的】旨在分析显微组织对钢轨闪光焊焊接接头纵断面硬度的影响规律。【方法】采用光学电子显微镜(Optical electron microscope,OEM)、扫描电镜(Scanning electron microscope,SEM)及电子背散射衍射(Electron backscatter diffractio...
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【目的】旨在分析显微组织对钢轨闪光焊焊接接头纵断面硬度的影响规律。【方法】采用光学电子显微镜(Optical electron microscope,OEM)、扫描电镜(Scanning electron microscope,SEM)及电子背散射衍射(Electron backscatter diffraction,EBSD)等技术手段,对某厂生产的欧标R260级珠光体钢轨闪光焊焊接接头不同微区硬度、显微组织、珠光体片层间距、晶粒取向及尺寸等特征参数进行表征与研究,阐明接头不同微区显微组织及晶粒特征参数对接头纵断面硬度影响规律。【结果】结果表明,在一定的工艺条件下,采用平均值和反映测量误差正态分布特点的标准误差值来表示特定材质珠光体钢轨中珠光体片层间距更准确;晶粒尺寸的大小较珠光体片层间距对珠光体钢轨接头纵断面硬度的影响更为明显。【结论】为钢轨成分设计及其焊接工艺的优化提供了理论依据。
The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of ...
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The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of 80-200 μm and two different environments （distilled water and hydrazine solution at temperatures from 25 to 90 ℃） were selected. The results show that the ratio of Ft/Fn is lower in distilled water than that in hydrazine solution at the same temperature in the slip regime. Both the ratio of Ft/Fn and wear volume gradually increase with increasing medium temperature under the given normal load and displacement amplitude. Besides the displacement amplitude and load, temperature also plays an important role for wear behavior of Inconel 690 material. The increase of temperature could reduce the concentration of dissolved oxygen, and promote the absorption reaction of hydrazine and dissolved oxygen. As a result, the oxidative corrosion rate is obviously lowered. Abrasive wear and delamination wear are the main mechanisms of Inconel 690 in distilled water. However, in hydrazine solution the cracks accompanied by abrasive wear and delamination wear are the main mechanisms.
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