Contact mark. Intermittent marks adjacent to the weld line resulting from the electrical contact between the electrodes supplying the welding current and the pipe surface.
触点痕。由于供焊接电流的电极与管子表面间的电接触，致使在焊缝线附近产生不连续痕迹。
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This article introduces weld formation of low carbon steel, stainless steel and al alloy by TIG welding in longitudinal intermittent alternative magnetic field.