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本文根据形貌、形成机制及防止措施的接触疲劳破坏分为“麻点”及“剥落”两类。麻点的初裂缝是在表面交变切应力的作用下从表面产生并倾斜发展,然后,在进入裂缝的润滑油所造成的压力作用下,金属小块从表面崩落。剥落是在交变的主切应力τyz(45°)或正交切应力τyz的作用下产生。两者都在次表层出现最大值,可使次表层的金属产生塑变或进一步形成裂缝,此后,次表层裂缝将平行于表面扩展;同时,从表面还会形成次生裂缝,其将垂直于表面扩展并与次表层的塑变区或裂缝连接。主裂缝继续平行于表面扩展,最后走出表面,使金属小块从表面剥落而形成小坑。对于表面硬化的零件,如其硬化层太薄或心部太软,则剥落可能沿过渡层产生,称为“硬化层剥落”。
According to the morphology, formation mechanism and contact fatigue damage prevention measures are divided into “pitting” and “spalling” two categories. The initial crack in pitting is generated and tilted from the surface under the action of alternating surface shear stress, and then the metal nodules break down from the surface under the pressure caused by the oil entering the crack. Spalling is produced by alternating primary shear stress τyz (45 °) or quadrature shear stress τyz. Both occur at the subsurface maximum, allowing the subsurface metal to be plasticized or further cracked, after which subsurface cracks will extend parallel to the surface; at the same time, secondary cracks will form on the surface, which will be perpendicular to The surface expands and joins with the plastic zone or crack in the subsurface. The main crack continues to extend parallel to the surface and finally emerges from the surface, causing small pieces of metal to peel off the surface. For case-hardened parts, where the hardened layer is too thin or the core is too soft, flaking can occur along the transition layer, known as “hardened layer flaking.”