不同水深下水下湿法焊接电弧引弧温度计算

Calculation of Arc Ignition Temperature of Underwater Wet Welding Under Different Water Depths

水下湿法焊接技术近年来得到了广泛应用,但目前对水下湿法焊接引弧过程的物理本质的研究很少。首先搭建了水下湿法焊接电弧光谱诊断平台,同步采集不同水深条件下焊接过程中的电流、电压及光谱信号,对不同水深条件下水下湿法焊接引弧阶段进行界定,高速摄像机拍摄水下湿法焊接引弧过程以更直观观察引弧过程中电弧、气泡等水下动态变化。在此基础上,设置光谱仪延时,分别采集了引弧5,10,15,20及25 ms的光谱信号;改变水深条件,得到不同水深条件下引弧不同时刻的电弧光谱图。根据谱线选取原则综合分析,选取Fe元素作为计算水下湿法焊接引弧电弧温度的特征元素。引弧不同时刻均选取了五组数据,运用统计分析的方法对五组数据做平均化处理,以保证计算结果的准确性和可靠性。从Fe元素谱线中选取了五条合适的谱线作为计算水下湿法焊接引弧过程电弧温度的目标谱线,再利用玻尔兹曼图示法分别计算了不同水深条件下引弧不同时刻的水下湿法焊接电弧等离子体温度。结果表明:在相同水深条件下,引弧过程中电弧等离子体温度是随着引弧时间的不断增加而不断变化的,但其变化趋势并不是简单的线性增加,而是分别在引弧的不同时刻出现峰值;随着水深的增加,水下湿法焊接电弧等离子体的温度也随着上升,但其电弧温度的上升趋势开始变缓慢,40 m水深相对于20 m水深的电弧温度上升量要低于20 m水深条件下相对0.3 m水深条件下的电弧温度上升量。伴随着水深的增加,水下环境压力增大造成电弧进一步压缩,但压缩量有限。由于电弧被压缩,弧光的强度也增大。通过光谱分析的方法,从电弧物理的角度获悉水下湿法焊接引弧过程的物理本质,对认识电弧建立过程中微观击穿机理及实际生产中进一步提升引弧过程的稳定性提供了重要参考。

Underwater wet welding technology has been widely used in recent years,but there are few pieces of research on the physical nature of underwater wet welding arcing process now.In this paper,an underwater wet welding arc spectrum diagnosis platform was set up,voltage and spectrum signals in the welding process were collected simultaneously under different water depth conditions to define the arcing stage of underwater wet welding.The high-speed camera recorded the arcing process of underwater wet welding to observe the underwater dynamic changes such as arc and bubble more intuitively.On this basis,spectral signals of 5,10,15,20 and 25 ms were collected by the spectrometer,the arc spectrum at a different time under different water depth conditions was obtained by changing the water depth condition.According to the principle of line selection,the Fe elements were selected as the characteristic elements to calculate the arc temperature of underwater wet welding.We selected five sets of data at a different time of arc initiation and averaged them by statistical analysis method to ensure the accuracy and reliability of the calculation results.Five suitable lines were selected from the Fe element line as the target line to calculate the arc temperature of underwater wet welding arc-initiating process.And the plasma temperature of underwater wet welding at different time under different water depth conditions was calculated by Boltzmann graphic method.The results show that the arc plasma temperature changes with the increase of arc initiation time,but its variation trend is not a simple linear increase,but a peak at different times of arc initiation.With the increase of water depth,the temperature of underwater wet welding arc plasma also increases,but the rising trend of arc temperature begins to change slowly.The increase in arc temperature at a depth of 40 m relative to a depth of 20 mis lower than the increase in arc temperature at a depth of 20 mrelative to a depth of 0.3 m.With the increase of water depth,the increase of underwater environment pressure causes the arc to be further compressed,but the compression amount is limited.As the arc is compressed,the intensity of the arc light also increases.By means of spectral analysis,the physical nature of the arc-initiating process in wet-welding under water is learned from the perspective of arc physics,which provides an important reference for understanding the micro-breakdown mechanism during the arc establishment process and further improving the stability of the arc starting process in actual production.