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本文借助光学显微镜,扫描电镜,透射电镜分析了 HT200灰铸铁经激光处理后硬化带中显微组织特征,并进行快速滑动磨损试验,探讨显微组织和耐磨性的关系。实验结果表明:HT200经激光熔化处理后表层显微组织为树枝(M+A′)+树枝间莱氏体(M+A′+Fe_3C);经激光不熔化处理后表层显微组织为马氏体针团+A′+G。激光处理后耐磨性显著提高。HT200经激光熔化处理后其磨损经历塑性变形—萌生显微裂纹—裂纹扩展—断裂;而经不熔化处理后其磨损经历裂纹扩展一断裂。HT200经激光处理后表面形成变态莱氏体、消除或减少石墨、细化显微组织、增加残余奥氏体量对提高耐磨性有利。
In this paper, the microstructures of HT200 gray cast iron after laser treatment were analyzed by means of optical microscope, scanning electron microscope and transmission electron microscope, and the rapid sliding wear test was carried out to investigate the relationship between microstructure and wear resistance. The experimental results show that the surface microstructure of HT200 after laser melting is the branch (M + A ’) and the interdendrite (M + A’ + Fe_3C). The microstructure of the surface after laser melting is Markov Acupuncture + A ’+ G After laser treatment wear resistance increased significantly. After being laser melted, HT200 wear and deform under plastic deformation - germinating microcrack - crack propagation - fracture; while after being infiltrated, HT200 wear undergoes crack propagation and fracture. HT200 laser treatment of the surface of the formation of metamorphic ledeburite, eliminate or reduce graphite, refine the microstructure, increase the amount of retained austenite beneficial to improve the wear resistance.