改善316不锈钢摩擦学性能的表面织构与离子氮化复合处理

发布时间：2018-10-15 09:41

【摘要】：奥氏体不锈钢是不锈钢中使用量和生产量最大的一种钢材，以其优异的耐腐蚀性能和加工成形性能成为现代工业中重要的工程材料之一，但受表面硬度低、耐磨性差等缺点的制约，一般不能用于制作摩擦配副零部件。因此，提高奥氏体不锈钢表面的摩擦学性能，扩展其使用范围具有十分重要的意义。区别于传统的表面改性技术，本文利用奥氏体不锈钢对Cl-点腐蚀敏感性高的特点，在较高浓度的NaCl溶液中对316不锈钢进行电化学处理获得表面织构，并在此基础上对获得表面织构的试样进行离子氮化复合处理以获得更加优异的性能，并分别对表面织构化和离子氮化复合处理后的试样在干摩擦条件下和脂润滑条件下的摩擦学性能及磨损机理进行了研究。主要研究结果如下： 1、电化学处理表面织构化 (1)、采用电化学处理方法成功在316不锈钢表面获得凹坑、沟槽等织构组织，对织构进行表征后发现不同浓度的NaCl电解液会对表面织构的尺寸造成一定的影响。 (2)、在干摩擦条件下，表面织构化后的试样在滑动初期具有储存磨屑降低磨损的作用，但由于其本身易磨损的缺点导致一段时间后织构被磨损破坏，且最终的磨损失重量只比基体略有减少，并没有大幅提高其在干摩擦条件下的摩擦学性能。表面织构化后的试样在与GCr15钢球和Si3N4陶瓷球对磨时都发生了粘着磨损和磨粒磨损，同时还伴有氧化磨损。 (3)、在脂润滑条件下，，未经处理的基体在滑动过程中的摩擦系数和最终的磨损失重量与干摩擦条件下相近；在三种不同浓度的氯化钠电解液(20%，15%，10%)下经过电化学处理后的试样均具有良好的减摩作用，摩擦系数在整个滑动过程中都保持在0.15以下，织构起到了储存油脂提供二次润滑源的作用，磨损失重量较干摩擦条件下明显减小，极大提高了316不锈钢在脂润滑条件下的摩擦学性能。其在与GCr15钢球对磨时只发生了塑性变形，与Si3N4陶瓷球对磨时发生了磨粒磨损和塑性变形。 2、离子氮化复合处理 (1)、对表面织构化后的试样进行离子氮化处理，处理后试样保留了原有的表面结构及尺寸，渗氮层厚度约为45μm，主要由ε相、γ′相、CrN相组成，表面硬度由257HV0.1升高到了1048HV0.1。 (2)、在干摩擦条件下，复合处理后试样的摩擦系数波动很小，且在摩擦结束后表面织构并未被完全破坏，在整个过程中起到了储存磨屑减小磨损的作用，与复合处理前的磨损失重量相比大幅减小，提高了316不锈钢在干摩擦条件下的摩擦学性能。其与GCr15钢球对磨时发生了微切削磨损并伴随有氧化现象，与Si3N4陶瓷球对磨时发生了粘着磨损和磨粒磨损并伴随有氧化现象。 (3)、在脂润滑条件下，复合处理后试样的摩擦系数波动很小，且在整个摩擦过程中低于0.13，同样起到了储存油脂提供二次润滑源的作用，磨损失重量与之前相比有了进一步的减小。其与GCr15钢球对磨时只发生了轻微的塑性变形，与Si3N4陶瓷球对磨时只发生了轻微的磨损。
[Abstract]:Austenitic stainless steel is one of the most used steel in stainless steel, and its excellent corrosion resistance and processability becomes one of the most important engineering materials in modern industry, but it is restricted by the disadvantages of low surface hardness, poor wear resistance and so on. It can't be used to make friction fit sub-parts. Therefore, it is very important to improve the tribological properties of austenitic stainless steel surface and extend its application range. Different from the traditional surface modification technology, the surface texture was obtained by electrochemical treatment of 316 stainless steel in a higher concentration of NaCl solution by using the characteristics of high sensitivity of the austenitic stainless steel to Cl-point corrosion. The tribological properties and wear mechanism of samples subjected to surface texturing and ion nitriding were studied under dry friction conditions and grease lubrication conditions. The main findings are as follows: 1. Electrochemical treatment surface The structure (1) adopts an electrochemical treatment method to successfully obtain pits and grooves on the surface of the 316 stainless steel. Different concentrations of NaCl electrolyte are found to be responsible for the size of surface-woven structures after the texture is characterized a certain effect. (2) under dry friction conditions, the sample after surface texturing has the effect of reducing wear at the initial stage of sliding, but due to the disadvantages of easy wear of the sample, the woven structure is damaged after a period of time, and the final grinding loss weight slightly less than the substrate and does not significantly increase its dry friction strip, The tribological properties of the specimens are the same as the abrasive wear and abrasive wear of the specimen after surface texturing. It is also accompanied by oxidation wear. (3) Under the condition of grease lubrication, the friction coefficient and the final grinding loss weight of the untreated matrix in the sliding process are similar to those under dry friction conditions; in three different concentrations of sodium chloride, The electrolytic solution (20%, 15%, 10%) has a good anti-friction effect after being subjected to electrochemical treatment, and the friction coefficient is kept under 0. 15 during the whole sliding process, the structure plays a role of storing grease to provide a secondary lubricating source, and the grinding loss weight It is obviously reduced under the condition of dry friction, and the 316 stainless steel is greatly improved in grease The tribological properties of Si3N4 ceramic balls during grinding were studied. Wear and plastic deformation of abrasive particles and 2, the ion nitriding composite treatment (1), carrying out ion nitriding treatment on the surface-woven sample, reserving the original surface structure and the size of the sample after treatment, and the thickness of the nitriding layer is about 45 mum. and the surface hardness is 257H. V0. 1 was raised to 1048HV0.1. (2), under dry friction condition, the friction coefficient of the sample after composite treatment was very small, and the surface texture was not completely destroyed after the friction was finished. and is greatly reduced compared with the grinding loss weight before the composite treatment, The tribological properties of 316 stainless steel under dry friction condition were studied. in that condition of grease lubrication, the fluctuation of the friction coefficient of the sample under the condition of grease lubrication is small, The effect of the source, the weight of the grinding loss is further reduced compared to the previous one, and only slight plastic deformation occurs when the steel ball is milled with the steel ball.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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