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针对水导润滑轴承在高硼水溶液的工作介质中发生的汽蚀现象,拟采用激光熔覆的方法提高其表面性能。通过激光熔覆技术在304奥氏体不锈钢表面熔覆了Ni40合金粉末,研究了激光功率对熔覆层组织与性能的影响。用半导体激光器对304奥氏体不锈钢进行激光熔覆,形成厚约为0.8 mm的熔覆层。试样分别用金相显微镜(OM)、扫描电子显微镜(SEM)进行显微组织分析,用维氏硬度计测量熔覆层剖面硬度梯度,用磨损试验机测试熔覆层的耐磨性能,并在硼酸溶液中进行耐蚀性能检测试验。实验结果表明:Ni40熔覆层主要由γ-Ni及铬的化合物组成,功率影响熔覆层组织大小及元素分布,但并未引起物相的变化;相比基体,熔覆层硬度明显提高,且随功率增加而下降,熔覆层厚度随功率增加而加厚;熔覆层在摩擦磨损过程中产生的质量损失约为1.5×10~(-2)g左右,且随功率的增加而减少;熔覆层在硼酸溶液中的耐蚀性随激光功率的增加有所提高。
Aiming at the cavitation occurred in the work medium of water-borne lubricating bearings in high-boron aqueous solution, laser cladding method is proposed to improve its surface properties. The Ni40 alloy powder was cladding on 304 austenitic stainless steel by laser cladding, and the effect of laser power on the microstructure and properties of the cladding layer was studied. 304 austenitic stainless steel was laser clad with a semiconductor laser to form a cladding having a thickness of about 0.8 mm. The samples were analyzed by OM and SEM respectively. The hardness gradient of the cladding layer was measured by Vickers hardness tester. The wear resistance of the cladding layer was tested by a wear tester. Corrosion resistance test in boric acid solution. The experimental results show that the Ni40 coating is mainly composed of γ-Ni and chromium compounds, and the power affects the microstructure and elemental distribution of the coating, but does not change the phase. Compared with the matrix, the hardness of the coating increases obviously, And decreases with increasing power. The thickness of the cladding increases with increasing power. The mass loss of the cladding during friction and wear is about 1.5 × 10 ~ (-2) g, and decreases with the increase of power The corrosion resistance of the cladding layer in boric acid solution increased with the increase of laser power.