重载接触试验与机理分析

Mechanism Analysis of Overloading Contact Test

摘要:

为研究重载接触工作状况下机械零部件的耐磨性，提高零部件的使用寿命，以某重载装备伸缩臂的托辊系统为研究对象，进行托辊系统与支撑板重载接触试验，研究摩擦试件的磨损机理.使用光学显微镜、扫描电子显微镜和能谱分析仪对试件磨损后的表面宏/微观形貌、化学成分和塑性变形情况进行分析.结果表明，在重载工作状况下，随着磨损次数的增加，支撑板的磨损机理呈现为综合的磨粒磨损和黏着磨损；而由于托辊的硬度比支撑板硬度高，所以托辊的磨损机理主要是磨粒磨损，伴随着轻微的黏着磨损.通过对磨损后托辊截断面的显微组织观察，发现表层片状珠光体局部区域有位错、组织破坏等现象，这表明重载接触下托辊已经发生塑性变形.

关键词:重载接触; 托辊系统; 磨损机理; 表面形貌

Abstract:

Taking the roller system of the heavy equipment telescopic boom as the research object, the overloading contact tests of the rolller system and the supporting plate was conducted to investigate the wear mechanism of friction specimens, in order to improve the wear resistance and the life span of the mechanical parts. By using scanning metallography, SEM and EDS techniques, the surface morphologies, chemical composition and plastic deformation of the worn test specimens were analyzed. The results show that under heavyduty conditions and with the increase of wear times, the wear mechanism of the supporting plate is both abrasive and adhesive. However, the wear of the roller is less serious than that of the supporting plate because of its higher hardness. The wear mechanism of the roller is both abrasive and mild adhesive. A study of the worn roller layer microstructure indicates that lamellar pearlite has dislocation movement and microstructure damage in the local area, which shows that the plastic deformation of the roller has happened under overloading contact.

Key words:overloading contact; roller system; worn mechanism; surface morphology