Laser beam welding is used to fabricate the 7A52 aluminum alloy plates.Effects of shielding gas and defocusing on porosities are investigated.Porosities are divided into hydrogen porosities and keyhole-induced porosit...Laser beam welding is used to fabricate the 7A52 aluminum alloy plates.Effects of shielding gas and defocusing on porosities are investigated.Porosities are divided into hydrogen porosities and keyhole-induced porosities.With the increasing flow rate of the front shielding gas,the porosity ratio firstly decreases,then increases.The porosity ratio is lowest under the flow rate of 25 L/min.When the flow rate is 30 L/min,the porosity ratio is higher because the large flow rate can affect the stability of the keyhole.The porosity ratio is also higher when the flow rate is less than 25 L/min because the protection is weakened.With the increase of the defocusing,the porosity ratio firstly decreases,then increases.When the defocusing is-2 mm,the porosity ratio is lowest.When the defocusing is more than 0 mm or less than-4 mm,the porosity ratio is higher due to the movement of the instable keyhole.展开更多
保护气体是决定CO2激光-MAG(metal active gas)电弧复合焊接工艺稳定性、焊接熔深和接头质量的关键因素,但是相关的试验研究报道有限。对此,采用He-Ar和CO2-Ar混合气体在Q235钢板上进行了CO2激光-MAG电弧复合焊接工艺研究。结果表明,保...保护气体是决定CO2激光-MAG(metal active gas)电弧复合焊接工艺稳定性、焊接熔深和接头质量的关键因素,但是相关的试验研究报道有限。对此,采用He-Ar和CO2-Ar混合气体在Q235钢板上进行了CO2激光-MAG电弧复合焊接工艺研究。结果表明,保护气体种类与配比对工艺和焊缝特征有明显的影响。He-Ar焊缝能够得到更大的焊接熔深和焊缝硬度。CO2-Ar中的CO2在高温下分解形成氧进入熔池后改变了表面张力系数,进而改变了熔池流动方向,导致在CO2≥30%后形成平整的焊缝余高,焊缝电弧区和激光区的过渡更加平滑。当CO2含量>30%后,复合焊接工艺稳定性变差,焊缝硬度急剧降低。展开更多
基金the National Natural Science Foundation of China(Grant No.51905273)Natural Science Foundation of Jiangsu Province(Grant No.BK20190472).
文摘Laser beam welding is used to fabricate the 7A52 aluminum alloy plates.Effects of shielding gas and defocusing on porosities are investigated.Porosities are divided into hydrogen porosities and keyhole-induced porosities.With the increasing flow rate of the front shielding gas,the porosity ratio firstly decreases,then increases.The porosity ratio is lowest under the flow rate of 25 L/min.When the flow rate is 30 L/min,the porosity ratio is higher because the large flow rate can affect the stability of the keyhole.The porosity ratio is also higher when the flow rate is less than 25 L/min because the protection is weakened.With the increase of the defocusing,the porosity ratio firstly decreases,then increases.When the defocusing is-2 mm,the porosity ratio is lowest.When the defocusing is more than 0 mm or less than-4 mm,the porosity ratio is higher due to the movement of the instable keyhole.
文摘保护气体是决定CO2激光-MAG(metal active gas)电弧复合焊接工艺稳定性、焊接熔深和接头质量的关键因素,但是相关的试验研究报道有限。对此,采用He-Ar和CO2-Ar混合气体在Q235钢板上进行了CO2激光-MAG电弧复合焊接工艺研究。结果表明,保护气体种类与配比对工艺和焊缝特征有明显的影响。He-Ar焊缝能够得到更大的焊接熔深和焊缝硬度。CO2-Ar中的CO2在高温下分解形成氧进入熔池后改变了表面张力系数,进而改变了熔池流动方向,导致在CO2≥30%后形成平整的焊缝余高,焊缝电弧区和激光区的过渡更加平滑。当CO2含量>30%后,复合焊接工艺稳定性变差,焊缝硬度急剧降低。
