| 摘要: |
| 采用等离子堆焊技术在Z2CN1810不锈钢表面堆焊Ni60合金粉末熔覆层。应用扫描电镜、电子探针、X射线衍射仪、显微硬度计等测试手段，研究焊接电流和送粉速度对Ni60合金等离子堆焊层组织结构和显微硬度的影响。结果表明：堆焊层显微硬度较基材有明显提高，并且在熔合区域出现明显的硬度过渡和元素扩散区。焊接电流为110 A时堆焊层显微硬度为630 HV。随着焊接电流增大或送粉速度降低，堆焊层硬度和熔合区硬度梯度均明显降低。堆焊层出现了明显的组织梯度，包括熔合区、近熔合区树枝晶区(针状、条状、小花状)和近表层等轴晶区(块状、片状)。焊接电流增加，近表面区域小花状共晶结构并未消失，体积含量增大。送粉速度降低，堆焊层近熔合线区域针状结构变粗大。送粉速度为6 g/min时，堆焊层中部区域出现了具有方向性的长条状和分离的块状硼化物。 |
| 关键词: 等离子堆焊 电流 送粉速度 显微组织 显微硬度 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金(11072045) |
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| Influence of Parameters on Microstructure and Microhardness of Ni60 Alloy Hardfacing by Plasma Transferred Arc Welding |
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GE Yan–liu， DENG De–wei， TIAN Xin， GUAN Meng1,2
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1. School of Material Science and Engineering， Dalian University of Technology， Dalian, Liaoning 116024;2. Shenyang Blower Works Group Corporation， Shenyang 110869
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| Abstract: |
| The Ni60 alloy powder was deposited on the surface of Z2CN1810 stainless steel by plasma transferred arc welding. The microstructure and microhardness of the hardfacing with different welding currents and powder feed rates were characterized by scanning electron microscope, Xray diffraction, electron microprobe and hardness tester. The results show that the microhardness of the coating improves a lot, the phenomenon of hardness transition and elements diffusion is observed in the fusion area. The microhardness of coating with current of 110 A is about 630 HV while the hardness of the coating and the hardness gradient both decrease with higher currents or lower powder feed rates. Microstructural gradient is observed including fusion area, dendrite (needlelike, striplike and floretlike) near the interface and equiaxial structure (bulklike and platelike) near the surface in the coating. As current increases, the floretlike eutectic structures don’t disappear and the volume ratio increases. As powder feed rate decreases, the needlelike structures become more bulky. The striplike and separated bulklike borides are observed in the intermediate part of the coating with powder feed rate of 6 g/min. |
| Key words: plasma transferred arc welding (PTAW) current powder feed rate microstucture microhardness |
