The opening angle refers to the angle between the two edges of the tube blank before the extrusion roller. The size of the opening angle is related to the stability of the burning process and has a great impact on welding and quality. When the opening angle is reduced, the distance between the edges also Decrease, thereby enhancing the proximity effect. Under other conditions being the same, the heating temperature of the edge can be increased, thereby increasing the welding speed. If the opening angle is too small, the distance from the convergence point to the middle line of the extrusion roller will become longer. This results in the edges not being squeezed at high temperatures, which will reduce weld quality and increase power consumption.
Actual production experience shows that the longitudinal position of the movable guide roller can be adjusted to adjust the opening angle, which usually varies between 2 and 6°. When the guide roller cannot be adjusted longitudinally, it can be adjusted by using the thickness of the guide ring or pressing down the closed hole pattern. Adjust the size of the opening angle.
The placement position of the inductor has a great influence on the welding quality. When it is far away from the center line of the extrusion roller, the heating time is long and the heat affected zone is wide, which reduces the welding strength. On the contrary, insufficient edge heating will also reduce the welding strength. The inductor should be placed concentrically with the pipe, and the distance between its front end and the middle line of the extrusion roller is approximately equal to or less than the diameter of the pipe.
The placement position of the resistor (magnetic rod) not only has a great impact on welding and speed, but also has a great impact on quality. Practice has proven that when the front end of the resistor is exactly at the middle line of the extrusion roller, the flaring strength and flattening strength will decrease. Better, the geometric size of the welded pipe blank and the width and thickness deviation of the pipe blank will change the heating temperature and extrusion amount of the edge. Qualified products need to meet the standards.
If there are bends, sickle bends, and corrugations on the edge of the tube blank, it will deviate from the pass shape when passing through the forming machine, causing both sides of the strip to bend. Poor adjustment of the rollers will also cause the strip to deviate or the tube blank to deform, affecting the The quality of welding may be poor or the welding may not be possible at all.
Welded pipes for low-pressure fluid transportation are also called ordinary welded pipes, commonly known as black pipes. Galvanized welded pipes for low-pressure fluid transportation are also called galvanized electric welded steel pipes, commonly known as white pipes. Ordinary carbon steel wire casings are used in electrical appliances such as industrial and civil construction, mechanical equipment installation, etc. Steel pipes used to protect wires during installation projects. Straight seam electric welded steel pipes are steel pipes in which the weld seam is parallel to the longitudinal direction of the steel pipe.
High-frequency welded pipe is based on the principle of electromagnetic induction and the skin effect, proximity effect and eddy current thermal effect of AC charges in the conductor, so that the steel at the edge of the weld is locally heated to a molten state, and through the extrusion of the roller, the butt weld is inter-crystalline. High-frequency welded pipe is a kind of induction welding, which does not require welding filler, does not produce welding and spatter, has a narrow heat-affected zone, beautiful shape, and good welding and mechanical properties. Therefore, it is commonly used in the production of steel pipes.
