An experimental setup to excite ultrasonic by modulating electrical arc was applied in the submerged arc welding （SAW） process of 09 MnNiDR steel to study its effect on quality of the welds. Arc-excited ultrasonic energy refines grains of the welds and more acicular ferrite （ AF） appears in the fusion zone. It also enhances impact toughness of the joints at -70 ℃ significantly. With the ultrasonic of 50 kHz, the toughness is improved by 47% in the fusion zone and by 82% in the heataffected zone （HAZ）. The fractography of welds shows that the fracture is changed from cleavage fracture to gliding fracture while applying ultrasonic vibration.
通过调制电弧激发出超声并应用于09M nN iDR钢的埋弧自动焊过程。采用常规焊接工艺参数,并加入不同频率的电弧超声进行焊接工艺评定。金相分析表明,在电弧超声作用下,焊缝结晶组织明显细化,焊缝区针状铁素体增加。冲击实验表明,接头的低温冲击韧性提高。尤其是在50 kH z超声作用下,-70℃下焊缝区和热影响区冲击韧性值较未加入超声时均提高了近50%,相应的断口扫描电子显微镜(SEM)分析表明接头由解理断裂转变为韧性断裂。电弧超声还可降低接头对焊接热输入的敏感性,提高生产效率。实验证明电弧超声是提高低温钢焊接接头性能的一种有效的方法。
