采用不同频率的高频脉冲电流耦合交流CMT(cold metal transfer)焊,分别以ER4043及ER5356焊丝为填充材料,对2060铝锂合金进行焊接。结果表明,不同频率的高频脉冲电流对焊接接头的气孔数量及大小影响显著。耦合高频电流焊接后,焊缝中心的...采用不同频率的高频脉冲电流耦合交流CMT(cold metal transfer)焊,分别以ER4043及ER5356焊丝为填充材料,对2060铝锂合金进行焊接。结果表明,不同频率的高频脉冲电流对焊接接头的气孔数量及大小影响显著。耦合高频电流焊接后,焊缝中心的气孔数量减少,气孔大都集中在熔合线及焊缝边缘;与填充ER4043焊丝相比,填充ER5356焊丝的气孔数量少,尺寸也较小。不同的脉冲频率均能不同程度地细化显微组织,填充焊丝为ER4043,脉冲频率为40 k Hz时,组织细化现象显著,接头各区的硬度较高;填充焊丝为ER5356,脉冲频率为60、70 k Hz时,组织细化现象显著,接头各区的硬度较高。展开更多
A new type of variable polarity welding power modulated with high-frequency pulse current is developed. Series of high-frequency pulse current is superimposed on direct-current-electrode-negative （DCEN）, which can i...A new type of variable polarity welding power modulated with high-frequency pulse current is developed. Series of high-frequency pulse current is superimposed on direct-current-electrode-negative （DCEN）, which can improve the crystallization process in the weld bead as a result of the electromagnetic force generated by pulse current. Digital signal processor （DSP） is used to realize the closed-loop control of the first inverter, variable polarity output of the second inverter and high-frequency pulse current superposition.展开更多
AA 2219-0 Al-Cu alloy single bead welds were obtained by hybrid ultrahigh frequency pulse variable polarity gas tungsten arc welding （HPVP-GTAW） process with pulse frequency varying from 25 kHz to 70 kHz. Weld hardn...AA 2219-0 Al-Cu alloy single bead welds were obtained by hybrid ultrahigh frequency pulse variable polarity gas tungsten arc welding （HPVP-GTAW） process with pulse frequency varying from 25 kHz to 70 kHz. Weld hardness characteristics which mainly depicted by microhardness and its gradient were investigated systematically. The results show that pulse frequency has a great effect on the hardness characteristics. The weld zone microhardness and its gradient with different pulse frequency present an evident fluctuant trend. The fluctuation of gradient is slight, illustrating that the mierostructure is uniform with pulse frequcncy varied from 35 kHz to 60 kHz. The fusion zone microhardness and its gradient foUow the similar trends but fluetuate greatly. Maximum value of gradient appears around the fusion boundary due to the coarse and non- uniform microstrueture. The maximum gradient at 60 kHz is only 25.5 % of that at 45 kHz. According to the study, the best hardness characteristics are achieved at 60 kHz frequency.展开更多
文摘采用不同频率的高频脉冲电流耦合交流CMT(cold metal transfer)焊,分别以ER4043及ER5356焊丝为填充材料,对2060铝锂合金进行焊接。结果表明,不同频率的高频脉冲电流对焊接接头的气孔数量及大小影响显著。耦合高频电流焊接后,焊缝中心的气孔数量减少,气孔大都集中在熔合线及焊缝边缘;与填充ER4043焊丝相比,填充ER5356焊丝的气孔数量少,尺寸也较小。不同的脉冲频率均能不同程度地细化显微组织,填充焊丝为ER4043,脉冲频率为40 k Hz时,组织细化现象显著,接头各区的硬度较高;填充焊丝为ER5356,脉冲频率为60、70 k Hz时,组织细化现象显著,接头各区的硬度较高。
文摘A new type of variable polarity welding power modulated with high-frequency pulse current is developed. Series of high-frequency pulse current is superimposed on direct-current-electrode-negative （DCEN）, which can improve the crystallization process in the weld bead as a result of the electromagnetic force generated by pulse current. Digital signal processor （DSP） is used to realize the closed-loop control of the first inverter, variable polarity output of the second inverter and high-frequency pulse current superposition.
基金The research is supported by the National Natural Science Foundation of China （No. 51005011 ） the Fundamental Research Funds for the Central Universities.
文摘AA 2219-0 Al-Cu alloy single bead welds were obtained by hybrid ultrahigh frequency pulse variable polarity gas tungsten arc welding （HPVP-GTAW） process with pulse frequency varying from 25 kHz to 70 kHz. Weld hardness characteristics which mainly depicted by microhardness and its gradient were investigated systematically. The results show that pulse frequency has a great effect on the hardness characteristics. The weld zone microhardness and its gradient with different pulse frequency present an evident fluctuant trend. The fluctuation of gradient is slight, illustrating that the mierostructure is uniform with pulse frequcncy varied from 35 kHz to 60 kHz. The fusion zone microhardness and its gradient foUow the similar trends but fluetuate greatly. Maximum value of gradient appears around the fusion boundary due to the coarse and non- uniform microstrueture. The maximum gradient at 60 kHz is only 25.5 % of that at 45 kHz. According to the study, the best hardness characteristics are achieved at 60 kHz frequency.
