磁场与粉煤灰联合作用下TIG焊电弧行为

Study on the behavior of TIG welding arc under the combined action of magnetic field and fly ash

为了研究活性剂与高频磁场联合作用对电弧行为影响及熔深改变机理,使用粉煤灰作为活性剂对Q235钢进行A-TIG焊,并在焊接过程中施加高频纵向磁场,实现两者的联合作用.试验中对不同的涂覆量下A-TIG焊缝形貌进行分析,发现当涂覆量为0.3 mg/mm^(2)时,熔深增加最为明显,在此涂覆量下引入1.5 kHz高频纵向磁场,熔深达到2.70 mm,为普通氩弧焊的1.8倍,但磁场频率继续增加,熔深则会出现下降趋势.采集焊接过程中电弧形貌、电流密度、电弧力及电弧温度的变化数据,分析活性剂与高频纵向磁场对TIG焊的联合作用机理,发现活性剂与磁场的联合作用能够改变外部磁场在等离子体内的分布使带电粒子受到更大的洛伦兹力,导致电弧在一定范围内进一步收缩;同时,与磁控-TIG相比,能够改善高频磁场引起的“磁抽吸”现象,使电弧热量更加集中.

In order to study the effect of activating agent and high frequency magnetic field on arc behavior and the change mechanism of penetration depth,A-TIG welding of Q235 Steel was carried out with fly ash as activating agent,the high frequency longitudinal magnetic field is applied in the welding process to realize the combined effect of the two.It is found that the penetration depth increases most obviously when the coating amount is 0.3 mg/mm^(2),and the longitudinal magnetic field of 1.5 kHz is introduced under the coating amount,the penetration depth reaches 2.70 mm,which is 1.80 times of that of the conventional argon arc welding,but the penetration depth will decrease with the increase of magnetic field frequency.By collecting the data of arc shape,current density,arc force and arc temperature during welding,the mechanismof combined action of activating flux and high frequency longitudinalmagnetic field on TIG welding is discussed,it isfound that the combined action of the active agent and the magneticfield can change the distribution of the external magneticfield in the plasma,causing the charged particles to be moreLorentz force,causing the arc to contract further within a certainrange,compared with magnetron-TIG,it can improve the“Magnetic suction”phenomenon caused by high frequencymagnetic field and make the arc heat more concentrated.