Treatment of welding joint problem: burning protective mirror表现: 短时间内保护镜损坏出现烧点,保护镜出光面有点状损坏点,呈现黑色或白色中黑点Performance:In a short period of time, the protective mirror is damaged and burned, and the light-emitting surface of the protective mirror is a bit damaged, showing black or white black spots.原因分析