材料期刊网

目的 探究一种可以显著提高65Mn弹簧钢耐磨性能的工艺,以满足其在高磨损环境下的使用性能要求.方法 通过正交试验对65Mn进行QPQ处理,利用金相组织观察、SEM扫描及能谱分析、磨粒磨损等手段,探究不同氮碳共渗温度、共渗时间、氧化温度和氧化时间对试样显微组织结构及耐磨性能的影响,优化出常规QPQ和深层QPQ处理方案.结果 经过QPQ处理的试样,渗层组织由外向内为氧化物层、疏松层、化合物层和扩散层.经深层QPQ处理的试样,在化合物层和扩散层中间有一层含氮奥氏体层.氧化物层的主要物相是Fe3O4,化合物层的主要物相是Fe3N.QPQ处理后的试样经面扫描后,C、N、O元素分布有一定规律,其中C元素集中分布在试样表面,N元素主要集中在致密化合物层,O元素主要集中在样品表层和疏松空洞之中.结论 深层QPQ工艺为640℃共渗2 h、350℃氧化40 min时,试样氧化层厚度达到15μm,化合物层厚30μm,奥氏体层厚10μm.深层QPQ处理后的65Mn的耐磨性能优异,磨损率达到0.166 mg/m.

The work aims to explore a technique which can significantly improve wear resistance of 65Mn spring steel to meet the performance requirements in high wear environment. 65Mn was treated with QPQ by virtue of orthogonal test to ex-plore the effects of nitriding temperature, nitriding time, oxidation temperature and oxidation duration on the microstructure and wear resistance of the samples by means of metallographic observation, SEM scanning and energy spectrum analysis as well as abrasive wear. And the conventional QPQ and thorough QPQ treatment schemes were optimized. The results of QPQ analysis showed that samples treated with QPQ were composed of oxide layer, loose layer, compound layer and diffusion layer from the outside towards the inside. In the samples treated with thorough QPQ, there was a layer of nitrogenous austenitic layer between the compound layer and diffusion layer. Main phase of the oxide layer was Fe3O4 while that of the compound layer was Fe3N. The distribution of C, N and O elements in the sample treated with QPQ after line-by-line scanning exhibited some regularity, i.e., the C elements were mainly on the surface, the N elements were mainly in the dense compound layer while the O elements were mainly on the surface and in loose holes. In the thorough QPQ process, the oxide layer is 15μm thick, the compound layer 30μm and the austenite layer 10μm when co-cementation continues for 2 hours at 640℃ and oxidation process 40 minutes at 350℃ . After thorough QPQ treatment, the wear rate of 65Mn is up to 65Mn and is provided with excellent wear resistance while the wear rate is 0.166 mg/m.