Laser multi\|layer cladding experiments were performed on the substrate of DD3 single crystal with FGH95 powder as cladding material. The solidification microstructure in the sample was investigated. It was found th...Laser multi\|layer cladding experiments were performed on the substrate of DD3 single crystal with FGH95 powder as cladding material. The solidification microstructure in the sample was investigated. It was found that the solidification microstructure was greatly influenced by the crystallography orientation of the substrate and the local solidification conditions. When the angle between the preferred orientation of the single crystal and the direction of heat flow in the cladding layer is less than 30°, single crystal cladding layers were acquired. Otherwise the crystallography orientation of the cladding layer will deviate from the orientation of the substrate and the microstructure with polycrystalline appears. Meanwhile, even when the experiments were performed on the same preferred crystal surface, the solidification microstructures will be different distinctly resulting from the variation of the local solidification conditions. The secondary arms were degenerated and the primary arm spacing was about 10\|20 μm. Further investigation shows that the phases of the cladding layer are mainly made up of γ,γ′ , the flower\|like γ/γ′ eutectic and carbide. The morphology of γ′ was cubical and the size is less than 0.1μm. {展开更多
传统的核电机组主设备内表面防腐蚀堆焊采用双层埋弧自动焊工艺,焊材用量大,耗时高,堆焊层缺陷较多,单层均质电渣堆焊工艺的技术及经济指标更为优异,但因焊材质量问题一直未能得到实际应用。通过实验选用了OK Band 11.72焊带与OK Flux 1...传统的核电机组主设备内表面防腐蚀堆焊采用双层埋弧自动焊工艺,焊材用量大,耗时高,堆焊层缺陷较多,单层均质电渣堆焊工艺的技术及经济指标更为优异,但因焊材质量问题一直未能得到实际应用。通过实验选用了OK Band 11.72焊带与OK Flux 10.10焊剂的焊材组合,采用电渣堆焊工艺熔敷单层均质防腐蚀层,其熔敷金属在综合机械性能、抗晶间腐蚀能力、稳定的抗热裂纹形成能力、避免再热裂纹等方面满足标准要求,并具有非金属夹杂含量低,焊接缺陷少等特点。经论证可以用于VVER型核电机组稳压器内表面防腐蚀层的堆焊,并总结了实际堆焊时应注意的问题与改进措施。展开更多
Straight plates, hollow columns, ear-like blade tips, twist plates withdirectional solidification microstructure made of Rene 95 superalloys were successfully fabricatedon Nickel-base superalloy and DD3 substrates, re...Straight plates, hollow columns, ear-like blade tips, twist plates withdirectional solidification microstructure made of Rene 95 superalloys were successfully fabricatedon Nickel-base superalloy and DD3 substrates, respectively. The processing conditions for productionof the parts with corresponding shapes were obtained. The fabrication precision was high and thecomponents were compact. The solidification microstructure of the parts was analyzed by opticalmicroscopy. The results show that the solidification microstructure is composed of columnardendrites, by epitaxial growth onto the directional solidification substrates. The crystallographyorientation of the parts was parallel to that of the substrates. The primary arm spacing was about10 mum, which is in the range of superfine dendrites, and the secondary arm was small or evendegenerated. It is concluded that the laser metal forming technique provides a method to manufacturedirectional solidification components.展开更多
基金National Key Basic Research Development Program me of china(No.G2 0 0 0 0 672 0 5 -3 )
文摘Laser multi\|layer cladding experiments were performed on the substrate of DD3 single crystal with FGH95 powder as cladding material. The solidification microstructure in the sample was investigated. It was found that the solidification microstructure was greatly influenced by the crystallography orientation of the substrate and the local solidification conditions. When the angle between the preferred orientation of the single crystal and the direction of heat flow in the cladding layer is less than 30°, single crystal cladding layers were acquired. Otherwise the crystallography orientation of the cladding layer will deviate from the orientation of the substrate and the microstructure with polycrystalline appears. Meanwhile, even when the experiments were performed on the same preferred crystal surface, the solidification microstructures will be different distinctly resulting from the variation of the local solidification conditions. The secondary arms were degenerated and the primary arm spacing was about 10\|20 μm. Further investigation shows that the phases of the cladding layer are mainly made up of γ,γ′ , the flower\|like γ/γ′ eutectic and carbide. The morphology of γ′ was cubical and the size is less than 0.1μm. {
文摘传统的核电机组主设备内表面防腐蚀堆焊采用双层埋弧自动焊工艺,焊材用量大,耗时高,堆焊层缺陷较多,单层均质电渣堆焊工艺的技术及经济指标更为优异,但因焊材质量问题一直未能得到实际应用。通过实验选用了OK Band 11.72焊带与OK Flux 10.10焊剂的焊材组合,采用电渣堆焊工艺熔敷单层均质防腐蚀层,其熔敷金属在综合机械性能、抗晶间腐蚀能力、稳定的抗热裂纹形成能力、避免再热裂纹等方面满足标准要求,并具有非金属夹杂含量低,焊接缺陷少等特点。经论证可以用于VVER型核电机组稳压器内表面防腐蚀层的堆焊,并总结了实际堆焊时应注意的问题与改进措施。
基金This research was financially supported by the National High Technology Research and Development Program of China (No.2001AA337020)the Development Plan of State Key Fundamental Research of China (No. G2000067205-3)
文摘Straight plates, hollow columns, ear-like blade tips, twist plates withdirectional solidification microstructure made of Rene 95 superalloys were successfully fabricatedon Nickel-base superalloy and DD3 substrates, respectively. The processing conditions for productionof the parts with corresponding shapes were obtained. The fabrication precision was high and thecomponents were compact. The solidification microstructure of the parts was analyzed by opticalmicroscopy. The results show that the solidification microstructure is composed of columnardendrites, by epitaxial growth onto the directional solidification substrates. The crystallographyorientation of the parts was parallel to that of the substrates. The primary arm spacing was about10 mum, which is in the range of superfine dendrites, and the secondary arm was small or evendegenerated. It is concluded that the laser metal forming technique provides a method to manufacturedirectional solidification components.
