摘要
目的研究离子渗氮的温度及时间对4Cr5MoSiV钢渗氮层组织、表面硬度及耐磨性的影响,获得提高硬度、耐磨性的最优工艺参数。方法对4Cr5MoSiV钢表面进行离子渗氮处理,渗氮温度分别为450、480、510、540℃,保温时间分别为5、10、15、20h。利用维氏显微硬度仪测量渗层深度及表面硬度;利用X射线衍射仪分析渗层物相组成;利用摩擦磨损试验机评价试样耐磨性;通过扫描电镜观察表面磨痕区域。结果离子渗氮渗层表面的物相主要为γ'-Fe4N相和ε-Fe2~3N相。在实验范围内,随着温度的升高或时间的增加,材料渗层深度、表面硬度增加,磨损率减少,但当温度过高或时间过长时,表面硬度下降,磨损率增加。在480℃的条件下进行20h离子渗氮的材料,表面具有最好的摩擦学性能,表面硬度为1147HV0.2,磨损率为2.13×10^-5mm^3/(N·m),渗氮层深0.24mm,化合物层深14.05μm,摩擦系数为0.45,磨损状态为磨粒磨损。结论离子渗氮是适合于变截面弹簧的表面强化方式,可以在材料表面形成具有一定厚度、均匀分布的渗氮层组织,显著提升表面硬度和耐磨性,降低摩擦系数。
The work aims to study the effect of temperature and time of ion nitriding on the structure, surface hardness and wear resistance of nitriding layer of 4Cr5MoSiV steel, and to obtain the optimum technological parameters for improving wear resistance and hardness. The surface of 4Cr5MoSiV steel was treated by ion nitriding with the nitriding temperatures of 450, 480, 510 and 540 degrees, and the holding time of 5, 10, 15 and 20 h, respectively. The penetration depth and surface hardness were measured by micro Vickers hardness tester. The phase composition was measured by XRD. The wear resistance of the samples was evaluated by friction and wear tester. The wear scar area was observed by scanning electron microscopy. The phase composition of the compound layer on the surface of nitriding layer was mainly γ'-Fe4N and ε-Fe2~3N. In the experimental range, with the increase of temperature or time, the penetration depth and surface hardness of the material increased, and the wear rate decreased. However, when the temperature was too high or the time was too long, the surface hardness decreased and the wear rate increased. The surface of plasma nitriding material had the best tribological properties at 480 degree and 20 h. The surface hardness was 1147 HV0.2, wear rate was 2.13×10^-5 mm^3/(N·m), nitriding layer depth was 0.24 mm, compound layer depth was 14.05 μm, friction coefficient was 0.45, and wear state was abrasive wear. Ion nitriding is a surface strengthening method suitable for variable cross-section springs and can form a nitriding layer with a certain thickness and uniform distribution on the surface of materials to significantly improve the surface hardness and wear resistance, and reduce the friction coefficient.
作者
刘建睿
严宏志
李算
田昊
秦娟
LIU Jian-rui;YAN Hong-zhi;LI Suan;TIAN Hao;QIN Juan(National Key Laboratory for High-performance Complex Manufacturing, Central South University, Changsha 410083, China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第8期199-205,共7页
Surface Technology
基金
国家自然科学基金项目(51575533)~~
关键词
变截面弹簧
4CR5MOSIV钢
离子渗氮
渗氮层组织
耐磨性
表面硬度
variable cross-section spring
4Cr5MoSiV steel
ion nitriding
nitriding layer structure
wear resistance
surface hardness
