用 4 5k W高功率激光器对 Ni Cr Si B合金在送粉激光熔覆下裂纹形成的材料成分、熔覆工艺、微观组织等因素进行研究。实验表明 ,裂纹是由于熔覆层中大量的多种硬质相以及硬质相的不良分布形态所造成的高脆性 ,难以承受熔覆过程产生的较...用 4 5k W高功率激光器对 Ni Cr Si B合金在送粉激光熔覆下裂纹形成的材料成分、熔覆工艺、微观组织等因素进行研究。实验表明 ,裂纹是由于熔覆层中大量的多种硬质相以及硬质相的不良分布形态所造成的高脆性 ,难以承受熔覆过程产生的较大拉应力所致。解决激光熔覆层裂纹问题的主要方向应是从工艺上降低熔覆过程的残余拉应力 ,同时从成分搭配和快速凝固特性上使得 Ni Cr Si B熔覆层微观组织中的硬质强化相细小均匀地弥散析出 。展开更多
NiCrSiB modified layer was synthesized on Monel 400 by laser cladding,aiming at improving cavitation erosion and corrosion resistance.The microstructure,chemical composition,phase constituents and microhardness were i...NiCrSiB modified layer was synthesized on Monel 400 by laser cladding,aiming at improving cavitation erosion and corrosion resistance.The microstructure,chemical composition,phase constituents and microhardness were investigated using scanning electron microscope(SEM),energy-dispersive spectrometer(EDS),X-ray diffractometry(XRD) and microhardness tester.The cavitation erosion and corrosion behaviors of the modified layer were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement,respectively.Experimental results show that by varying the laser fluence,a hard NiCrSiB modified layer with little airholes,cracks or other defects could be obtained.NiCrSiB modified layer is ~1.1 mm in thickness.The microstructure of the modified layer exhibits cellular dendrite,flake-like dendrite and multiple eutectic phase.The modified layer is mainly composed of γ-Ni solid solution,chromium carbide(Cr_(7)C_(3)and Cr_(23)C_(6)) and Ni_(3)B.The microhardness of the modified layer is ~6.8 times that of Monel 400 substrate.Both the cavitation erosion and corrosion resistance of the modified layer are improved.In the cavitation erosion test,the cumulative erosion loss and erosion loss rate of the modified layer are one order of magnitude lower than that of the substrate.In the electrochemical corrosion test,the corrosion potentials of the substrate and the modified layer are similar.The corrosion current densities of the substrate and the modified layer are 11.12 and 1.95 μA·cm^(-2),respectively.By comparing their corrosion current densities,the corrosion resistance of the modified layer is about 5.7 times that of the substrate.展开更多
采用高频感应熔覆技术,在12Cr Mo V合金结构钢材质的锅炉管表面进行了采用热喷涂、水玻璃作为黏结剂冷预置涂层、高频感应同步送粉器直接将合金粉末送于锅炉管表面3种工艺方法制备Ni Cr Si B耐磨合金涂层实验研究,用SEM和能谱仪分析了...采用高频感应熔覆技术,在12Cr Mo V合金结构钢材质的锅炉管表面进行了采用热喷涂、水玻璃作为黏结剂冷预置涂层、高频感应同步送粉器直接将合金粉末送于锅炉管表面3种工艺方法制备Ni Cr Si B耐磨合金涂层实验研究,用SEM和能谱仪分析了基体与熔覆层界面和熔覆层间的微观组织及成分,开展了硬度测试实验.结果表明:在熔覆电流为830 A、熔覆频率为250 k Hz的条件下,热喷涂法得到的熔覆层与基体有明显的间隙;水玻璃作为黏结剂冷预置涂层法获得的熔覆层有夹渣且表面不平整;而同步送粉法得到的熔覆层表面平整,熔覆层和基体间有明显的锯齿状白亮带,表明熔覆层和基体形成良好的冶金结合,熔覆层平均硬度为310 HV,是基体硬度的2倍.可见同步送粉高频感应熔覆工艺相对于预涂层法高频感应熔覆具有环保、加工效率高、无空隙夹渣、圆柱面平整度高、低成本等明显优势。展开更多
高功率激光器为材料表面改性提供了新的手段,如激光热处理、激光熔敷、激光合金化和非晶化等。利用高功率激光在短时间内将预敷在基材表面的高合金层熔化,同时使基材微熔,两者产生冶金结合,以提高基材表面的耐磨性及耐蚀性,这种快速熔...高功率激光器为材料表面改性提供了新的手段,如激光热处理、激光熔敷、激光合金化和非晶化等。利用高功率激光在短时间内将预敷在基材表面的高合金层熔化,同时使基材微熔,两者产生冶金结合,以提高基材表面的耐磨性及耐蚀性,这种快速熔凝技术称为激光熔敷（Laser cladding）。为满足某种工况需要,我们在 A<sub>3</sub>钢上进行了 Fe 基和 Ni 基合金的激光熔敷,显著提高了涂层的抗蚀性能。展开更多
In this paper, NiCrSiB and CoWC35 powder has been used in laser cladding of gray cast iron. The cracking tendency has also been discussed. The cracks have been observed with a scan electron microscopy to analyze the c...In this paper, NiCrSiB and CoWC35 powder has been used in laser cladding of gray cast iron. The cracking tendency has also been discussed. The cracks have been observed with a scan electron microscopy to analyze the cracking mechanism. The results show that cracks have not appeared in NiCrSiB cladding. Nevertheless, the cracking tendency of CoWC35 cladding is extremely high and there are both cold cracks and hot cracks in the cladding. The cracking tendency of laser cladding depends on physical properties of the cladding material and plasticity and roughness of the cladding.展开更多
为激光熔覆快速柔性制造金属零件 (LRFM) ,研制了一种新型的同轴送粉喷嘴 ,制造了一些简单形状的 Ni Cr Si B合金零件 ,研究了这些金属零件的微观组织、成分均匀性、硬度分布和抗拉强度。要提高激光熔覆快速制造零件的精度必须保证制造...为激光熔覆快速柔性制造金属零件 (LRFM) ,研制了一种新型的同轴送粉喷嘴 ,制造了一些简单形状的 Ni Cr Si B合金零件 ,研究了这些金属零件的微观组织、成分均匀性、硬度分布和抗拉强度。要提高激光熔覆快速制造零件的精度必须保证制造过程的稳定性 。展开更多
文摘用 4 5k W高功率激光器对 Ni Cr Si B合金在送粉激光熔覆下裂纹形成的材料成分、熔覆工艺、微观组织等因素进行研究。实验表明 ,裂纹是由于熔覆层中大量的多种硬质相以及硬质相的不良分布形态所造成的高脆性 ,难以承受熔覆过程产生的较大拉应力所致。解决激光熔覆层裂纹问题的主要方向应是从工艺上降低熔覆过程的残余拉应力 ,同时从成分搭配和快速凝固特性上使得 Ni Cr Si B熔覆层微观组织中的硬质强化相细小均匀地弥散析出 。
基金financially supported by the National Key Research and Development Program of China (Nos. 2016YFB1100204,2013ZX06002-002)the National Natural Science Foundation of China (No.51271126)Shenyang Science and Technology Funded Project (No.F16-032-0-00)
文摘NiCrSiB modified layer was synthesized on Monel 400 by laser cladding,aiming at improving cavitation erosion and corrosion resistance.The microstructure,chemical composition,phase constituents and microhardness were investigated using scanning electron microscope(SEM),energy-dispersive spectrometer(EDS),X-ray diffractometry(XRD) and microhardness tester.The cavitation erosion and corrosion behaviors of the modified layer were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement,respectively.Experimental results show that by varying the laser fluence,a hard NiCrSiB modified layer with little airholes,cracks or other defects could be obtained.NiCrSiB modified layer is ~1.1 mm in thickness.The microstructure of the modified layer exhibits cellular dendrite,flake-like dendrite and multiple eutectic phase.The modified layer is mainly composed of γ-Ni solid solution,chromium carbide(Cr_(7)C_(3)and Cr_(23)C_(6)) and Ni_(3)B.The microhardness of the modified layer is ~6.8 times that of Monel 400 substrate.Both the cavitation erosion and corrosion resistance of the modified layer are improved.In the cavitation erosion test,the cumulative erosion loss and erosion loss rate of the modified layer are one order of magnitude lower than that of the substrate.In the electrochemical corrosion test,the corrosion potentials of the substrate and the modified layer are similar.The corrosion current densities of the substrate and the modified layer are 11.12 and 1.95 μA·cm^(-2),respectively.By comparing their corrosion current densities,the corrosion resistance of the modified layer is about 5.7 times that of the substrate.
文摘采用高频感应熔覆技术,在12Cr Mo V合金结构钢材质的锅炉管表面进行了采用热喷涂、水玻璃作为黏结剂冷预置涂层、高频感应同步送粉器直接将合金粉末送于锅炉管表面3种工艺方法制备Ni Cr Si B耐磨合金涂层实验研究,用SEM和能谱仪分析了基体与熔覆层界面和熔覆层间的微观组织及成分,开展了硬度测试实验.结果表明:在熔覆电流为830 A、熔覆频率为250 k Hz的条件下,热喷涂法得到的熔覆层与基体有明显的间隙;水玻璃作为黏结剂冷预置涂层法获得的熔覆层有夹渣且表面不平整;而同步送粉法得到的熔覆层表面平整,熔覆层和基体间有明显的锯齿状白亮带,表明熔覆层和基体形成良好的冶金结合,熔覆层平均硬度为310 HV,是基体硬度的2倍.可见同步送粉高频感应熔覆工艺相对于预涂层法高频感应熔覆具有环保、加工效率高、无空隙夹渣、圆柱面平整度高、低成本等明显优势。
文摘高功率激光器为材料表面改性提供了新的手段,如激光热处理、激光熔敷、激光合金化和非晶化等。利用高功率激光在短时间内将预敷在基材表面的高合金层熔化,同时使基材微熔,两者产生冶金结合,以提高基材表面的耐磨性及耐蚀性,这种快速熔凝技术称为激光熔敷（Laser cladding）。为满足某种工况需要,我们在 A<sub>3</sub>钢上进行了 Fe 基和 Ni 基合金的激光熔敷,显著提高了涂层的抗蚀性能。
文摘In this paper, NiCrSiB and CoWC35 powder has been used in laser cladding of gray cast iron. The cracking tendency has also been discussed. The cracks have been observed with a scan electron microscopy to analyze the cracking mechanism. The results show that cracks have not appeared in NiCrSiB cladding. Nevertheless, the cracking tendency of CoWC35 cladding is extremely high and there are both cold cracks and hot cracks in the cladding. The cracking tendency of laser cladding depends on physical properties of the cladding material and plasticity and roughness of the cladding.
