激光焊接不锈钢微间隙焊缝偏差角点检测法

Detection of seam deviation of micro butt gap in laser welding of 304 austenitic stainless steel based on corner point method

针对大功率(10 kW)光纤激光焊接304不锈钢紧密对接微间隙焊缝(焊缝间隙小于0.1 mm),通过高速像机摄取熔池近红外热像并分析其特征,分析和处理熔池热像特征,提取激光束偏离焊缝位置的信息,探索激光束与焊缝偏差的信息表征.利用激光深熔焊的匙孔效应,研究焊缝在固态与液态交界处不稳定边缘特征点,提出一种角点检测法实现微间隙焊缝偏差的检测.结果表明,熔池红外热像角点密集分布中心与焊缝偏差有密切的关系,通过角点分布密度可以有效判断焊缝偏差状态.

Infrared radiation from the molten pool contains plenty of welding status information including the characteristics of the seam deviation.Infrared images of the molten pool were captured by an infrared sensitive high-speed camera during high power(10kW) fiber laser butt joint welding of 304 austenitic stainless steel with micro-gap seam(seam gap width was less than 0.1mm).By analyzing the molten pool characteristics,the information of seam deviation was explored.A keyhole formed when the laser beam was focused on a weldment and the metal vaporized instantly.Features of the keyhole infrared images,especially the characteristics of conjunction between the solid and liquid zones with unstable burr edge of seam were studied.A corner point detection method was proposed to detect the microgap seam deviation in high power laser welding process.Experimental results showed that the dense distribution center of the corner points of a molten pool infrared image had a close relationship with the weld seam deviation.The micro-gap weld seam deviation status in high power fiber laser welding can be determined by the corner point distribution density.