高温快速盐浴渗氮提高拖拉机曲轴性能  

Improvement of tractor crankshaft properties by rapid high temperature salt bath nitriding

作　　者：戴明阳[1] 唐威[1] 孙斐[2,3] 胡静[1,2] 

机构地区：[1]常州大学材料科学与工程学院江苏省表面工程科学与技术重点实验室,常州213164 [2]常州大学江苏省光伏科学与工程协同创新中心,常州213164 [3]常州轻工技术职业学院机械工程系,常州213164

出　　处：《农业工程学报》2016年第9期40-44,共5页Transactions of the Chinese Society of Agricultural Engineering

基　　金：江苏省科技成果转化项目(BA2013078);江苏省研究生创新基金项目(SCZ100431322)

摘　　要：为提高拖拉机曲轴盐浴渗氮效率,选择用于生产拖拉机曲轴的常用材料45钢,分别进行不同保温时间的高温快速盐浴渗氮和常规盐浴渗氮。利用光学显微镜、X射线衍射仪、显微硬度计和电化学工作站对渗层的显微组织、物相、硬度和耐蚀性进行了测试和分析。研究结果表明:经过660℃×20 min高温盐浴渗氮处理后化合物层的厚度与560℃×140 min常规盐浴渗氮相近,表明高温盐浴渗氮可以显著缩短渗氮的时间。在化合物层厚度相近的情况下,高温盐浴渗氮处理后渗层中γ'-Fe4N相含量从常规盐浴渗氮的0.46增加到0.61,同时,截面最高硬度从常规盐浴渗氮的702提高到784 HV0.01,并且耐蚀性能也获得了提高。该研究可为提升盐浴渗氮技术应用于45钢拖拉机曲轴表面改性工艺方案提供参考。Salt bath nitriding is one of the most popular surface modification technologies to treat tractor＇s crankshaft for obtaining the required properties. Generally, several hours is needed to acquire the required layer depth in normal salt bath nitriding, and especially, it is almost impossible to get the required qualified deep layer depth due to the loose outermost surface layer formed at longer duration. Therefore, it is of significant value to improve its efficiency and get the required layer depth with good quality. In order to enhance the nitriding efficiency of tractor＇s crankshaft, AISI 1045 carbon steel, which is a type of common material used to produce tractor＇s crankshaft in industrial production, was selected as the testing material. Rapid salt bath nitriding was conducted at higher temperature of 660℃ instead of normally used 560℃. Then we compared normal salt bath nitriding with higher temperature salt bath nitriding for different nitriding time. Optical microscopy（OM）, X-ray diffraction（XRD）, micro-hardness testing and electrochemical workstation were employed for analyzing the microstructure, phase, micro-hardness and corrosion resistance of the tested material, respectively. The results show that compound layer（also called white layer） is formed at the outermost surface after salt bath nitriding under all conditions. The thickness of compound layer is only 3.8 μm nitrided at 560℃ for 20 min, which is too thin to effectively improve the surface hardness and corrosion resistance of AISI 1045 steel, and it is increased to 17.1 μm treated at higher temperature of 660℃ for 20 min, which is the same thickness as that nitrided at 560℃ for 140 min. Therefore, it can be concluded that higher temperature salt bath nitriding is much more efficient than normal salt bath nitriding. Meanwhile the main phases of compound layer are composed of ε-Fe2-3N and γ＇-Fe4 N nitrided under different conditions. But the relative contents of ε-Fe2-3N and γ＇-Fe4 N are different, which can b

关 键 词：拖拉机 温度 试验 曲轴 盐浴氮化 硬度 

分 类 号：TG156.8[金属学及工艺—热处理]