The oil casing
is short-circuited. The reason for this phenomenon is internal mechanical failure, such as roller or shaft eccentricity, or excessive welding power, or other reasons. As the welding speed increases, the extrusion speed of the tube billet slope will increase. This is conducive to extruding the liquid metal layers and oxides on both sides that have been heated to melt to a high-quality weld. At the same time, the welding speed can be increased and the heating time of the groove surface can be placed, so that the oil short-circuit formation of oxides is shortened, and the welding heat-affected zone is narrowed.
On the contrary, not only the heat-affected zone is wide, but the main etching layer of liquid metal formed on the groove surface will become thicker, and penetrating burrs will be produced, which will reduce the quality of the weld. However, when the output power is constant, the cold welding speed cannot be increased indefinitely. Otherwise, the heating on both sides of the billet groove will not reach the welding temperature, resulting in defects or no welding at all.
For stainless steel
, the oil short circuit ripple coefficient affects the shape of the weld. Capacitor filtering reduces the ripple to less than 1%. When welding stainless steel, the frequency is usually 200. The weld has better toughness, and the high frequency heat affected zone is smaller. . Usually on the inner and outer walls of the welded pipe, the countercurrent gushes out from the welding area. Medium, continuous foam can well indicate that the welding power is sufficient and the mechanical condition is stable and uneven. The dark welding condition is uneven and the welding quality is poor.