改善铸铁活塞环表面耐磨性能的热处理工艺研究

The Study on Heat Treatment Processes to Improve the Wear Resistance of Cast Iron Piston Ring Surface

摘要: 汽车用活塞环的工作环境恶劣、复杂，磨损是其最常见的失效形式，这对活塞环的表面性能提出了很高的要求。汽车活塞环常以普通灰铸铁为基体材料，表面利用电脉冲沉积技术镀有一层纳米晶Ni-Co合金镀层来提升工件的表面性能。本文主要研究了不同的热处理工艺对汽车活塞环基体和表面镀层的结构性能的影响。研究表明：高温热处理能够大幅提升基体的显微硬度，然而与此同时镀层的显微硬度也有着不同程度的下降。250℃低温退火能够少量的提升镀层的显微硬度，而随着退火温度的升高，镀层显微硬度下降。在不同各种热处理工艺中，250℃低温退火是提升性能的最佳方案。

Abstract: Due to the work environment of cars’ piston rings is hard and wear is the most common failure mode, surface performance of piston ring is very important. Piston rings are usually made of ordi-nary gray cast iron, and the surface is plated with a layer of nanocrystal ni-co alloy coating by elec-tric pulse deposition technology in order to improve the surface performance of the components. In this paper, the effects of different heat treatment processes on the structural performance of the piston ring substrate and surface coating were studied. The results show that: High-temperature heat treatment can greatly improve the microhardness of the matrix, however, the microhardness of the coating usually decreased in different degrees at that time. Low temperature annealing at 250˚C can slightly improve the microhardness of the coating, but with the increase of the annealing temperature, the microhardness of the coating decreases. In different heat treatment processes, low-temperature annealing at 250˚C is the best process to improve the performance.