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磨削加工往往是工件热处理之后的重要工序。磨削质量对工件使用寿命的影响很大,这一问题正日益引起人们的重视。研究表明,不正确地进行磨加工时,磨具与工件接触的瞬间,摩擦热可使工件表面极薄层的温度急剧升高,甚至达到相变温度以上,由此可带来以下表面缺陷: 1.工件表面可能发生二次淬火,在相变应力和磨削应力叠加作用下往往产生与磨削方向垂直的浅表龟裂。 2.当磨削冷却不良时,磨削热能使工件表面发生不同程度的回火乃至正火,俗称“烧伤”。这种缺陷可能在工件表面产生软点、软带。这对许多要求表面具有高疲劳强度的工件是不能容许的。
Grinding is often an important part of the workpiece after heat treatment. The quality of grinding has a great influence on the service life of the workpiece. This issue is increasingly aroused people’s attention. The results show that when the grinding process is not carried out correctly, the friction temperature can increase the temperature of the extremely thin layer on the surface of the workpiece even when the grinding tool is in contact with the workpiece, and even reach the phase transition temperature, which can bring the following surface defects: 1. The workpiece surface may occur secondary quenching, phase stress and grinding stress superimposed tend to produce vertical grinding direction and shallow surface cracks. 2. When the grinding cooling is poor, grinding heat to the workpiece surface to varying degrees of tempering and even normalizing, commonly known as “burn.” This defect may produce soft spots on the surface of the workpiece, soft belt. This is not tolerable for many workpieces that require high fatigue strength on the surface.