In order to decrease the metallurgical porosity and keyhole-induced porosity during deep penetration laser welding of Al and its alloys, and increase the mechanical properties of work-piece, the effects of welding par...In order to decrease the metallurgical porosity and keyhole-induced porosity during deep penetration laser welding of Al and its alloys, and increase the mechanical properties of work-piece, the effects of welding parameters such as laser power, welding speed and defocusing value on both kinds of porosities were systemically analyzed respectively, and the shape and fluctuation of plume of the keyhole were observed to reflect the stability of the keyhole. The results show that increasing laser power or decreasing laser spot size can lead to the rising of both number and occupied area of pores in the weld; meanwhile, the plume fluctuates violently over the keyhole, which is always companied with the intense metallic vapor, liquid metal spatter and collapsing in the keyhole, thus more pores are generated in the weld. The porosity in the weld reaches the minimum at welding velocity of 2.0 m/min when laser power is 5 kW and defocusing value is 0.展开更多
The welding fume has significant effects on the weld workers＇ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was ...The welding fume has significant effects on the weld workers＇ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was carried out. The purifying device was designed. The relationship between the corona discharge voltage and the purifying efficiency was investigated through experiments with different needle electrode numbers, different ring electrode numbers and different needle-plate distances. The results show that 5-needle double-ring electrode has the best efficiency; the purifying efficiency is increase with the lessening of the needle-plate distance and the increase of the discharge voltage. Using 5-needle double-ring electrode, the purifying efficiency reaches its maximum value 97.9% while the needle-plate distance is 6 cm, the discharge voltage is -35 kV. The purifying device has an excellent purifying effect on the welding fume.展开更多
基金Project(51204109)supported by the National Natural Science Foundation of China
文摘In order to decrease the metallurgical porosity and keyhole-induced porosity during deep penetration laser welding of Al and its alloys, and increase the mechanical properties of work-piece, the effects of welding parameters such as laser power, welding speed and defocusing value on both kinds of porosities were systemically analyzed respectively, and the shape and fluctuation of plume of the keyhole were observed to reflect the stability of the keyhole. The results show that increasing laser power or decreasing laser spot size can lead to the rising of both number and occupied area of pores in the weld; meanwhile, the plume fluctuates violently over the keyhole, which is always companied with the intense metallic vapor, liquid metal spatter and collapsing in the keyhole, thus more pores are generated in the weld. The porosity in the weld reaches the minimum at welding velocity of 2.0 m/min when laser power is 5 kW and defocusing value is 0.
文摘The welding fume has significant effects on the weld workers＇ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was carried out. The purifying device was designed. The relationship between the corona discharge voltage and the purifying efficiency was investigated through experiments with different needle electrode numbers, different ring electrode numbers and different needle-plate distances. The results show that 5-needle double-ring electrode has the best efficiency; the purifying efficiency is increase with the lessening of the needle-plate distance and the increase of the discharge voltage. Using 5-needle double-ring electrode, the purifying efficiency reaches its maximum value 97.9% while the needle-plate distance is 6 cm, the discharge voltage is -35 kV. The purifying device has an excellent purifying effect on the welding fume.
