U75V货运重轨服役损伤及裂纹扩展行为研究

来源期刊：上海金属2011年第1期

论文作者：赵骏韦 陈宸 胡正飞 严益民 许玉德 周宇

文章页码：13 - 17

关键词：U75V轨道钢； 损伤； 裂纹扩展； 磨损； 纵向斜裂纹

Key words：U75V Rail Steels； Damage； Crack Propagation； Wear； Vertical Crack

摘    要：通过量为150 MGT的货运U75V重轨服役状态表面出现明显的磨损、裂纹、剥离掉块等损伤。硬度测试显示钢轨表层由于塑性变形已产生较大的形变强化。XRD测试和显微结构观察显示,在接触疲劳应力作用下,钢轨表层及近表层产生严重的塑性变形,表现为晶粒细化。内部生成的微裂纹和夹杂相互作用连接在一起形成扩展裂纹,裂纹扩展主要是穿晶形式。裂纹发展至某一阶段可能以纵向大角度向内扩展,导致钢轨断裂。

Abstract: Under the passing tonnage about 150 MGT,U75V rail steel was heavily damaged with the features of wear,cracking and spalling.Mechanical property test,X-ray diffraction inspection and microstructure observations showed that the surface hardness of U75V steel rose,the surface and subsurface of structures were highly deformed under the touched fatigue stress,the grains were fined.The tiny internal cracks acted with the inclusions to propagate the cracks further by transgranular mode,the crack might extend vertical inward,leading to rail breakage.