等离子弧焊接穿孔行为的声信号传感

使用高精度传声器采集穿孔型等离子弧焊接过程中的声音信号 ,围绕焊接过程中出现的“小孔效应” ,开展了等离子弧焊接熔透的声音信号传感方法的研究。结果表明 ,焊接过程中的声音信号在熔池的过渡阶段产生了剧烈的低频振动 ,与熔池的振动有关 ,说明声音信号的低频段分量中包含有熔池穿孔状态的信息。频域分析表明 ,声音信号的低频段分量 (0～ 10 0Hz) ,在熔池处于不同阶段时有明显的变化 ,熔池处于过渡阶段时其值大 ,穿孔后小 ,未穿孔时居中。据此 ,设计出了声音信号的A算法 ,用于识别焊接过程中熔池的穿孔状态 ,该算法可靠性较高 ,为等离子弧焊接熔透质量监测及闭环控制提供了前提条件

SOUND SENSING OF THE KEYHOLE BEHAVIORS IN PLASMA ARC WELDING

The characteristics of the sound emitted from plasma arc welding of stainless steel is investigated.It is found that the sound pressure at the non keyhole stage is lower than that at the keyhole stage In transition case,the weld pool,changing its state from non keyhole to keyhole or vice versa,vibrates considerably with lower frequency.The spectrum analysis of the sound signal shows that less than 100 Hz part of the sound is large on the transition stage,small on the keyhole stage and medium on the non keyhole stage.According to this information,a sensing technique is proposed to judge the keyhole status in plasma arc welding. It may be used in the detection of plasma arc welding penetration to control the welding quality.