激光-MAG复合焊接过程金属蒸气和背部熔池图像分析

Analysis of the Images of Metal Vapor and Bottom-molten Pool in Laser-MAG Hybrid Welding Process

在激光-MAG复合焊中,金属蒸气和背部熔池包含着大量的焊接状态信息。以316不锈钢和400低碳钢为试验对象,作异种材料复合焊接,并应用高速摄像机获取焊接过程中正面金属蒸气和背部熔池的实时图像。提取金属蒸气面积形态特征,结合背部熔池图像同步分析金属蒸气周期性变化规律并研究金属蒸气和焊接状态、焊缝成形之间的关系。以灰度共生矩阵(GLCM)方法分析图像纹理特征,并用能量、对比度和熵三个特征分析背部熔池与焊缝成形之间的关系。结果表明,所分析方法能有效反映金属蒸气的变化机理,金属蒸气和背部熔池与焊接状态之间的关联,为在线检测复合焊接质量提供依据。

In the process of laser-MAG hybrid welding, the metal vapor and bottom-molten pool include plenty of welding information. Taking the hybrid welding of 316 austenitic steel and 400 mild steel plates as example, two high-speed cameras are used to capture the real-time images of top-vapor and bottom-molten pool. Through extracting metal vapor area morphological feature, the cyclic variation rule of metal vapor is synchronously analyzed combining with the bottom-molten images. The relationship among metal vapor, welding status and weld formation is researched. Image texture features are analyzed by taking advantage of GLCM method(gray level co-occurrence matrix). Angular second moment energy, contrast and entropy of an image are used to explore the relationship between bottom-molten pool and the weld formation. Experiment results show that the proposed method can reflect the mechanism of metal vapor as well as the correlation among metal vapor, bottom-molten pool and welding status effectively. It provides a basis for real-time monitoring in laser-MAG hybrid welding process.