The welding of aluminum(Al)and steel has attracted more and more interest due to the weight reduction trend in vehicle and aerospace manufacturing industries.5182-O/HC260YD+Z lap joint was produced by friction stir we...The welding of aluminum(Al)and steel has attracted more and more interest due to the weight reduction trend in vehicle and aerospace manufacturing industries.5182-O/HC260YD+Z lap joint was produced by friction stir welding(FSW),and the microstructure and mechanical property of the joint were systemically characterized.The microstructure in horizontal direction of the Al and steel near interface was similar to their corresponding conventional friction stir welded joint.The joint was divided into stir zone of Al(ST-Al),stir zone of interface(ST-I),thermal-mechanically affected zone of steel(TMAZ-Fe)and base material of steel(BM-Fe)according to their distinct microstructure vertically.Three kinds of intermetallic compounds(IMCs)of FeAl_(3),FeAl and Fe_(3)Al were formed at the interface.The horizontal micro hardness distribution exhibited a hat shape and“M”shape in Al and steel,respectively.The hardest region of the joint was located at the ST-I,with a hardness of 175 HV−210 HV.The joint was fractured along the hook structure,with an average shear strength of 73.9 MPa.Fractural morphology of Al and steel indicted a cleavage fracture mode.展开更多
为了解决离线预防性试验监测京广高铁牵引变电所220 k V干式电流互感器存在的诸多问题,依据绝缘介损的物理模型,采用过零监测比较法,设计一套220 k V干式电流互感器实时在线监测装置。在设计过程中,认真分析了电流传感器、高次谐波、过...为了解决离线预防性试验监测京广高铁牵引变电所220 k V干式电流互感器存在的诸多问题,依据绝缘介损的物理模型,采用过零监测比较法,设计一套220 k V干式电流互感器实时在线监测装置。在设计过程中,认真分析了电流传感器、高次谐波、过零比较器失调电压和零漂以及环境温湿度等因素对tanδ值测量精度的影响。并针对影响精度的不同因素,提出了相应的技术改进措施。现场运行情况表明,装置实时在线监测tanδ值结果与设备离线实测结果完全吻合,且运行稳定,工作可靠,满足现场运行的要求。展开更多
文摘The welding of aluminum(Al)and steel has attracted more and more interest due to the weight reduction trend in vehicle and aerospace manufacturing industries.5182-O/HC260YD+Z lap joint was produced by friction stir welding(FSW),and the microstructure and mechanical property of the joint were systemically characterized.The microstructure in horizontal direction of the Al and steel near interface was similar to their corresponding conventional friction stir welded joint.The joint was divided into stir zone of Al(ST-Al),stir zone of interface(ST-I),thermal-mechanically affected zone of steel(TMAZ-Fe)and base material of steel(BM-Fe)according to their distinct microstructure vertically.Three kinds of intermetallic compounds(IMCs)of FeAl_(3),FeAl and Fe_(3)Al were formed at the interface.The horizontal micro hardness distribution exhibited a hat shape and“M”shape in Al and steel,respectively.The hardest region of the joint was located at the ST-I,with a hardness of 175 HV−210 HV.The joint was fractured along the hook structure,with an average shear strength of 73.9 MPa.Fractural morphology of Al and steel indicted a cleavage fracture mode.
文摘为了解决离线预防性试验监测京广高铁牵引变电所220 k V干式电流互感器存在的诸多问题,依据绝缘介损的物理模型,采用过零监测比较法,设计一套220 k V干式电流互感器实时在线监测装置。在设计过程中,认真分析了电流传感器、高次谐波、过零比较器失调电压和零漂以及环境温湿度等因素对tanδ值测量精度的影响。并针对影响精度的不同因素,提出了相应的技术改进措施。现场运行情况表明,装置实时在线监测tanδ值结果与设备离线实测结果完全吻合,且运行稳定,工作可靠,满足现场运行的要求。
