Welding pressure is one of the main parameters of the welding process. After the two edges of the tube are heated to the welding temperature, common metal grains are formed under the action of the pressing force to form the welding with each other.
Due to the possible tolerances of the erw tube width and thickness, as well as fluctuations in the welding temperature and welding speed, changes in the welding pressure may be involved. The amount of welding extrusion is generally controlled by adjusting the distance between the squeeze rollers, or it can be controlled by the difference in the circumference of the squeeze rollers before and after.
The welding speed is also one of the main parameters of the welding process, which is related to the heating system, the deformation speed of the welding seam and the mutual crystallization speed. In the erw pipe, the welding quality increases with the welding speed. This is because the heating time is shortened to make the width of the edge heating zone narrower to shorten the time for forming the metal oxide. If the welding speed is decreased, not only the heating zone becomes wide but also the width of the melting zone varies with the input heat amount, burr larger. In low-speed welding, the heat input less difficult to weld, if not meet the required value prone to defects. Therefore, in the erw pipe, should be in the unit of the maximum allowable speed of mechanical equipment and welding equipment, according to different specifications of the species to choose the right welding speed.
The opening angle refers to the angle between the two edges of the tube before the squeeze roll. The size of the opening angle is related to the stability of the burning process, which has a great influence on the welding quality. When the opening angle is decreased, the distance between the edges is also reduced, so that the adjacent effect is strengthened. Under the other conditions, the heating temperature of the edge can be increased and the welding speed can be increased. If the opening angle is too small, the distance from the meeting point to the center line of the squeezing roller will be lengthened, resulting in the edge being not squeezed at the highest temperature, thus reducing the welding quality and increasing the power consumption. The actual production experience shows that the longitudinal position of the movable guide roller to adjust the size of the opening angle, usually between 2 ~ 6 ° change. In the case of the guide roller can not be adjusted vertically , you can use the thickness of the guide ring or press the closed hole to adjust the size of the opening angle.