QPQ处理法制备高硬度不锈钢表层  

Preparation of high hardness surface layer on stainless steel by QPQ treatment

作　　者：占卫君 卢建树[1] 

机构地区：[1]浙江工业大学材料科学与工程学院,浙江杭州310014

出　　处：《金属热处理》2016年第11期133-139,共7页Heat Treatment of Metals

摘　　要：为了提高1Cr18Ni9Ti奥氏体不锈钢的耐磨性能,研究了用QPQ复合处理法提高奥氏体不锈钢硬度的工艺技术。采用自制的氮碳共渗用盐,试验了不同处理温度和处理时间对不锈钢硬度及微观组织的影响。分析了氮碳共渗后,其渗层硬度随厚度的变化以及氮碳共渗前后的耐腐蚀性能。利用光学显微镜、SEM、XRD、EDS和数显显微硬度计,分别分析渗层显微组织和厚度、相组织、元素分布、表面硬度。结果表明:在600℃温度下,经150 min处理后的试样硬度可达1380 HV0.1,且渗层厚度达25μm。渗层由表及里分别是氮碳共渗外层、化合物层和过渡层,并且他们之间的分界很明显。其的化学组成主要由Cr N、ε-Fe_(2-3)(N、C)、γ-Fe和Fe_3O_4构成。随着盐浴处理时间和温度的增加,渗层厚度有先增加后减少的趋势。用极化曲线法测试试样的耐蚀性结果表明,不锈钢QPQ处理后耐腐蚀性能有所下降。In order to improve wear-resistance of austenitic stainless steel,QPQ treatment was carried out on 1Cr18Ni9 Ti stainless steel.Using self-prepared nitrocarburized salt bath,the influences of time and temperature on surface hardness,thickness and the corrosion resistance of the nitrocarburized layer were studied. The microstructure and element distribution of the nitrocarburized layer were analyzed by optical microscope,XRD,EDS and SEM. The results show that the QPQ treatment can greatly increase hardness of the steel. When the nitrocarburizing temperature is 600 ℃ and the holding time is 150 min,microhardness of the nitrided layer reaches 1380 HV0. 1 with the maximum depth of 25 μm. The nitrocarburized layer consists of an out layer of nitrocarburization,a compound layer and the transition layer,with an obvious interface between them. The composition of the nitrocarburized layer is Cr N,ε-Fe2-3（ N,C）,γ-Fe and Fe3O4 from outside to inside. With the increase of nitrocarburizing temperature and time,the nitrocarburized layer has a tendency to increase first,then decrease. Corrosion resistance of the nitrocarburized layer was evaluated by potentiodynamic polarization tests and it is indicated that the nitrocarburizing treatment reduces the pitting corrosion resistance of the stainless steel.

关 键 词：不锈钢 QPQ处理 显微组织 显微硬度 氮碳共渗层 耐腐蚀性能 

分 类 号：TG156.82[金属学及工艺—热处理]