Q235钢氩弧熔覆Fe-C-Cr-W系复合涂层的研究

发布时间：2018-04-27 13:16

本文选题：氩弧熔覆 + Q235钢　；参考：《吉林大学》2015年硕士论文

【摘要】：众所周知，机械零部件在工程应用中，磨损与腐蚀是其失效的主要形式。特别是随着现代工业的发展，，大量工程零部件处于复杂恶劣的工作环境中，因材料表面被磨损、腐蚀导致的材料失效，带来巨大的经济损失。为了提高性能和解决材料表面的磨损、腐蚀问题，本文以廉价的Q235钢作为基体，利用工艺简单灵活、成本低的氩弧熔覆技术在Q235钢表面熔覆三种铁基碳化物合金层，得到了具有实际应用价值的实验结果。通过改变熔覆时的电流，通入的气体流量，熔覆速度和预涂层厚度的大小，分析了熔覆层宏观形貌、微观组织结构及显微硬度的变化规律。获得了本实验条件下的最佳氩弧熔覆工艺参数，熔覆电流120A，预涂层厚度1.2mm，熔覆速度9cm/min，氩气流量8L/min。通过物相分析(XRD)和显微组织观察(SEM)，分析了熔覆层的组织形貌特点，发现熔覆层和母材界面处冶金结合效果良好。由界面向熔覆层方向，晶体形态由平面晶逐渐过渡到胞状晶和树枝晶。根据碳化物形成设计比例，在熔覆层内发生了原位合成反应，生成碳化物增强相。并且随着(C-Cr-W)粉末或者(C-W)粉末添加量的增加，氩弧熔覆原位合成碳化物增强相的数量也随之增多。在最佳氩弧熔覆工艺条件下，熔覆层显微硬度达到1300HV左右，大约是Q235钢硬度的6倍；同时，氩弧熔覆后熔覆层的耐磨损和抗腐蚀性能较基体有较大提高，熔覆层最小的磨损量只有基体的1/4，磨损机制主要是磨粒磨损、粘着磨损和氧化磨损；腐蚀后的最小失重量仅有基体的1/11。在本实验条件下，(C-Cr-W)粉末或者(C-W)粉末的比例达到70wt.%时，钨极氩弧熔覆层各性能最佳。
[Abstract]:As we all know, wear and corrosion are the main failure forms of mechanical parts in engineering application. Especially with the development of modern industry, a large number of engineering parts are in a complex and harsh working environment. Due to the wear and corrosion of the material surface, the material becomes invalid and brings huge economic losses. In order to improve the properties and solve the wear and corrosion problems on the surface of Q235 steel, three kinds of Fe-base carbide alloy layers were cladding on the surface of Q235 steel by using simple and flexible process and low cost argon arc cladding technology. Experimental results with practical application value are obtained. By changing the current, gas flux, cladding speed and the thickness of the precoating, the changes of the microstructure, microstructure and microhardness of the cladding layer were analyzed. The optimum technological parameters of argon arc cladding under the experimental conditions are obtained, the cladding current is 120A, the thickness of precoating is 1.2 mm, the cladding speed is 9 cm / min, and the argon flow rate is 8 L / min. The microstructure and morphology of the cladding layer were analyzed by phase analysis (XRD) and microstructure observation. It was found that the metallurgical bonding effect was good at the interface between the cladding layer and the base metal. From the interface direction to the cladding direction, the crystal morphology gradually transition from plane crystal to cellular crystal and dendrite. According to the carbides formation design ratio, the in-situ synthesis reaction took place in the cladding layer to form carbide reinforcing phase. With the increase of the amount of C-Cr-W- or C-W powder, the number of in-situ synthesized carbide enhancement phases by argon arc cladding also increases. Under the optimum argon arc cladding condition, the microhardness of the cladding layer is about 1300HV, which is about 6 times of that of Q235 steel, and the wear resistance and corrosion resistance of the cladding layer after argon arc cladding are much higher than that of the substrate. The wear mechanism of the coating is mainly abrasive wear, adhesion wear and oxidation wear, and the minimum weight loss after corrosion is only 1 / 11 of the matrix. When the ratio of C-Cr-W- or C-W powder is 70 wt.%, the properties of TIG arc cladding coating are the best.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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