Mo和Cu对Ni60A等离子喷焊层组织及性能的影响

发布时间：2018-06-19 22:05

本文选题：等离子喷焊 + 合金元素　；参考：《吉林大学》2016年硕士论文

【摘要】：在矿山开采、模具铸造和机械加工等领域,许多零部件所处工作环境恶劣,表面磨损和腐蚀常常是零部件失效的主要原因。为了提高零部件在使用过程中的耐磨性和耐蚀性,延长零部件的使用寿命,研究人员采用了激光熔覆和等离子喷焊等表面强化技术。其中等离子喷焊技术因具有消耗材料少,生产效率高,成品制备容易等优点,越来越多地受到业界重视。本文利用等离子喷焊技术在H13模具钢基体表面制备喷焊层,喷焊材料以Ni60A为基本合金粉末,分别在其中添加合金元素Mo和Cu后研究了喷焊层的耐磨与耐蚀性能。并对添加合金元素Mo强化后的喷焊层进行固溶和时效处理,研究了热处理工艺对喷焊层微观组织与性能的影响。Ni60A合金粉末加入合金元素Mo之后,所制备的等离子喷焊层显微组织得到细化,喷焊层中生成了Mo Si2、Mo2C、Mo3C2和Mo C等硬质相,硬质相弥散分布在喷焊层中。Mo3C2通过共析反应转变为Mo C和Mo2C,相互聚集形成椭圆形碳化物。固溶处理后,初生碳化物几乎全部溶解在喷焊层中,但仍有一定量的Mo2C和Mo C等未发生溶解;熔合区的粗大晶粒带消失,化学成分也更加均匀。磨料磨损试验表明:随着喷焊层中Mo含量的增加,喷焊层的耐磨性明显提高,Mo的添加量达到8%时,与Ni60A喷焊层相比,耐磨性提高了约30%。但Mo的加入量过多反而会降低喷焊层的耐磨性。固溶处理后喷焊层的组织与成分更加均匀,残余应力大幅度减小,合金元素Mo强化的喷焊层经固溶处理后的耐磨性能较未经热处理和时效处理的更好。电化学腐蚀试验表明:添加合金元素Mo的喷焊层的点蚀电位大幅增加,8%Mo/Ni60A喷焊层的耐点蚀性能较好。1%Cu/Ni60A喷焊层的点蚀电位Eb与Ni60A喷焊层相比提高了80m V,喷焊层也具有良好的耐点蚀性能。同时添加合金元素Mo和Cu所制备的喷焊层耐点蚀性能优于304不锈钢,利用喷焊合金粉末10%Mo+1.4%Cu/Ni60A所制备的喷焊层的耐点蚀性能最好。在10%HCl和10%H2SO4溶液中,单独添加合金元素Mo和Cu以及两者同时添加均能使得喷焊层的腐蚀电位Ecorr增大,腐蚀电流Icorr减小,抗均匀腐蚀能力提高。固溶处理后的喷焊层在10%HCl溶液中的腐蚀电位Ecorr增加了69.6 m V,耐蚀性能得到了提高。
[Abstract]:In the fields of mining, mold casting and mechanical processing, many parts are in a bad working environment, surface wear and corrosion are often the main reasons for the failure of parts. In order to improve the wear resistance and corrosion resistance of the parts and prolong the service life of the parts, the surface strengthening techniques such as laser cladding and plasma spray welding were adopted. Plasma spray welding technology has attracted more and more attention because of its advantages of low consumption of materials, high production efficiency and easy preparation of finished products. In this paper, plasma spray welding technology was used to prepare spray welding layer on the substrate of H13 die steel. Ni60A was used as the basic alloy powder, and the wear resistance and corrosion resistance of the spray welding layer were studied after the addition of Mo and Cu respectively. The effect of heat treatment on the microstructure and properties of the spray-welding layer was studied. The effect of heat treatment on the microstructure and properties of the spray-welding coating was studied after adding the alloy element Mo to the alloy powder, and the effect of heat treatment on the microstructure and properties of the spray-welding layer was studied. The microstructure of the plasma spray welding layer was refined. The hard phases such as Mo Si 2N Mo 2C C 2 Mo 3C 2 and Mo C 3 C were formed in the spray welding layer. The hard phase dispersed in the spray welding layer and changed to Mo C and Mo 2C by eutectoid reaction, and formed an elliptical carbide. After solution treatment, the primary carbides were almost dissolved in the spray welding layer, but some amounts of Mo2C and MoC were not dissolved, and the coarse grain bands in the fusion zone disappeared, and the chemical composition was more uniform. The abrasive wear test shows that with the increase of Mo content in the spray welding layer, the wear resistance of the spray welding coating is obviously improved when the addition amount of Mo is up to 8%, and the wear resistance of the spray welding layer is increased by about 30% compared with the Ni60A spray welding layer. However, the wear resistance of the spray welding layer will be reduced by the addition of Mo. After solution treatment, the microstructure and composition of the spray welding layer are more uniform, and the residual stress is greatly reduced, and the wear resistance of the spray welding layer strengthened by Mo alloy is better than that without heat treatment and aging treatment. The electrochemical corrosion test showed that the pitting corrosion potential of spray welding coating with Mo addition increased significantly, and the pitting corrosion resistance of spray welding coating with Mo / Ni60A was better than that of Ni60A coating. The pitting corrosion potential of spray welding coating was 80 MV higher than that of Ni60A spray welding coating, and the spray welding coating also had better pitting corrosion resistance than Ni60A spray welding coating. Good pitting resistance. The pitting corrosion resistance of the spray-welding coating prepared by adding alloy elements Mo and Cu is better than that of 304 stainless steel, and the pitting corrosion resistance of the spray-welding coating made of 10Mo 1.4 Cu/ Ni60A alloy powder is the best. In the solution of 10HCl and 10H2SO4, the addition of Mo and Cu alone and both of them can increase the corrosion potential, decrease the corrosion current and improve the uniform corrosion resistance of the spray welding coating. After solution treatment, the corrosion potential of spray welding layer in HCl solution increased by 69.6 MV, and the corrosion resistance was improved.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG174.4

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