硼铸铁缸套QPQ盐浴复合处理的组织和性能研究

利用扫描电子显微镜(SEM)分析了硼铸铁缸套QPQ(淬火-抛光-淬火)处理后的表面形貌、氮化层深度;采用401MVA型显微维氏硬度计测量试样显微硬度;在M-2000型磨损试验机上进行滑动磨损试验;采用10%NaCl水溶液浸泡法对其进行抗蚀性测试。研究结果表明:硼铸铁经QPQ盐浴复合处理后,得到了一定厚度的白亮层和扩散层,使金属零部件表面形成高硬度、高耐磨性能的氮化物层,组织和性能稳定,表层显微硬度最高达到1010HV0.1,是基体显微硬度的3倍以上。耐磨性和抗腐蚀性较渗氮前都有大幅度提高。并用该工艺方法对硼铸铁缸套进行了批量生产,实际应用表明可使硼铸铁缸套使用寿命大大提高,易于推广应用。

Effect of QPQ Complex Salt Bath Treatment on Microstructure and Properties of the Boron-Cast Iron Cylinder Liners

The surface morphology and depth of nitrided layer of the boron-cast iron cylinder liners,after QPQ(quench-polish-quench)complex salt-bath treatment,were analyzed by using SEM. The sliding wear resistance was tested on the M-2000 tester and the micro-hardness was tested using 401MVA microscopy hardness tester,also the corrosion resistance was tested in the 10%NaCl water by using immersing method. The experimental results indicate that a certain depth of white layer and diffusion layer of boron-cast iron can be obtained by using QPQ complex salt-bath treatment. The nitriding compound layer with higher hardness and wear resistance can also be obtained on the surface of the parts,which has stable microstructure and properties. The highest hardness on the surface layer is 1 010 HV0.1,which is 3 times higher than that of matrix. The boron-cast iron cylinder liners have been produced by using this treating method. The application indicated that the wear resistance,corrosion resistance and service life of the boron-cast iron cylinder liners have greatly been improved. The QPQ complex salt-bath treatment is a very useful method and easily applied process.