运用塑性指数进行密封材料的摩擦学设计

目的摩擦副的选配是一个十分复杂的问题,目前还没有一个通用的规范。机械端面密封材料副也是一个典型的摩擦副,其选择与所要密封的介质有关,密封材料副涉及高硬度材料(如硬质合金)及软质材料(如浸渍石墨、浸渍巴氏合金等)。材料选择范围大,材料性能差异也大,其内在本质并不清楚。旨在提出一种方法,为摩擦副材料的选择与表面设计提供依据。方法分析了G-W模型塑性指数的局限性,考虑了摩擦副硬度的匹配性,并以一对摩擦副系统的有效硬度代替G-W模型塑性指数中较软配副材料的硬度。同时采用因存在摩擦力导致真实接触面积增大的修正粘着理论对G-W模型塑性指数进行了修正,以期能够适应摩擦等复杂接触工况,并引入摩擦系数。结果塑性指数的区分度增大,反映了摩擦副的硬度匹配性,同时体现了与磨损率的相关性。结论对非超硬材料配副,系统的塑性指数越大,磨损率也越大。

Tribology Design of Sealing Materials Using Plastic Index

Friction pair selection for sealing face is a complex issue and no general specification has been proposed yet. The pair of mechanical face sealing materials, as a typical friction pair, shall be selected based on sealed media. The pair of sealing materials involved high hardness materials (such as cemented carbides) and soft materials (such as impregnated graphite and Babbitt alloy). A wide range of materials was available, performance of materials varied a lot and intrinsic nature was not understood. The paper aims to propose a method and provide basis for selection and surface design of friction pair materials. Limitations of plastic index from G-W model were analyzed. Hardness matching of friction pair was considered, system hardness of a friction pair was used to substitute hardness of softer material in the plastic index from G-W model. Meanwhile, modified adhesive theory (in which real contact area could be increased by friction force) was applied to modify the plastic index from G-W model, so as to adapt to complex contact conditions such as friction and introduce friction coefficient. The modified plastic index can be discriminated easily, and it can reflect the hardness matching of friction pair and correlation with wear rate. Generally, non-superhard materials with high plastic index are of higher wear rate; and the high plastic index is in direct proportion to high wear rate.