Slag mixture is a defect, which is easy to occur in welds, weld slag and non-metallic impurities. It may appear on surface of welds or at root of welds…
Any weld with slag will influence significantly on impact strength and flexibility of weld metal and decrease working capacity of welded connection under dynamic load.
·        Welding current is small, insufficient heat quantity to make metal melted and make slag unable to escape from welding area.
·        Welding edges are not clean or slag is not removed completely during tack weld or multi-layer weld.
·        Welding angle is not reasonable and welding speed is high.
·        Cold speed is so fast, making slag unable to escape.
·        Increase welding current appropriately. Execute welding by short arc and increase arc stopping time
·        Clean workpiece before welding. Remove slag on tack welds and weld layers.
·        Change properly the angle and method of moving welding rod. Lower welding speed to prevent slag from mixing into welding area or from melting ahead of welding area.