堆焊电流对镍基合金等离子堆焊层组织及性能的影响

Influence of welding current on microstructure and properties of nickel-based alloy hardfacing by plasma transferred arc welding

  • 摘要: 为了提高Z2CN18-10奥氏体不锈钢的耐磨性,采用等离子堆焊技术在其表面制备镍基合金堆焊层。借助扫描电子显微镜、能谱仪、X射线衍射仪、显微硬度计及摩擦磨损试验机,对不同堆焊电流条件下镍基合金等离子堆焊层显微组织、相结构、成分、显微硬度及耐磨性进行了系统的研究。结果表明,镍基合金堆焊层的相组成为γ-Ni固溶体与FeNi3,Cr23C6,Cr7C3,CrB的共晶组织。随着堆焊电流的增大,镍基合金堆焊层的组织由团簇花瓣状向水草状和细长的条状组织转变;当堆焊电流为110 A时,镍基堆焊层的平均显微硬度最大为898 HV,与基体的相对耐磨性为13.8,磨损机制为前期的粘着磨损和磨粒磨损以及后期形成的氧化磨损的混合机制。

     

    Abstract: In order to improve the abrasion resistance of Z2CN18-10 stainless steel, the nickel-based alloy powder was deposited on the Z2CN18-10 stainless steel by plasma transferred arc welding. The microstructures, phase structure, compositions, microhardness and wear resistance properties of the hardfacing layer with different welding currents were characterized by scanning electron microscope, energy disperse spectroscopy, X-ray diffractometer, microhardness tester and abrasion tester. The results show that the surfacing layer mainly consists of γ-Ni and precipitates such as FeNi3, Cr23C6, Cr7C3 and CrB. The microstructures of nickel base alloy surfacing layer vary from clusters of petals to aquatic plants and the banded structure with the increase of welding current. At the welding current of 110 A, the hardfacing layer possesses the highest average microhardness of 898 HV, and its wear resistance is the best, and its relative wear resistance is 13.76, compared with the substrate. Wear mechanism of the hardfacing layer is adhesive and abrasive wear early, and then oxidative wear later.

     

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