The straight sewing steel pipe is an important process in the production of straight steel pipes. Especially for API standards with high quality requirements and oil pipes, special pipes for machinery and equipment. These steel pipes not only have strict requirements in the quality of steel and welds, but also have high straight lines of steel pipes. It is required that because the deviation of linearity is directly related to the processing, connection, and twisting of the tube and the pipe holes of the tube and the conveyor tube. There are two types of processing of the existing tube -ending car -rotation and tool rotation. Most car silk processing uses a tube rotation, which requires higher linearity of the steel pipe.
There are many reasons for the bending of the steel pipe, such as the heat effects of welding seams during welding, the eccentricity of the formation, as well as compression, the imbalance of the bending power, and so on. But fundamentally, bending is the role of stress in the steel pipe. Simply put, bending is the uneven stress. So, is there no internal stress on straight steel pipes? no. The straight steel pipe also has internal stress, but the internal stress of the direct tube is less.
What is the internal stress? Temperature and external forces affect the interaction between a molecule when deformation. When the steel pipe is formed and welded, the welding temperature is also affected by the influence of these external formed bending. The cross section of the steel pipe is a ring -shaped, which will generate two basic stress on this ring area: parallel to the ring -shaped force and perpendicularity of the ring -shaped shape. The parallel stress will make the tube not round; the vertical stress will make the tube bent. Therefore, there is a cold diameter process during the production process of straight steel pipes, the purpose is to eliminate the internal stress of the steel pipe and increase the intensity of the use of straight steel pipes.
The pipe that needs to be straight from the feed device of the machine's left end (or right end) is sent to the lower roller of the straight machine, and the upper roller will exercise it to hold the pipe, stop at the corresponding position. The upper and lower rollers are tilted with a certain angle with the axis of the straight tube.
The three upper rollers were pressed on the pipes under the action of their respective hydraulic cylinders. The two lower rollers were driven by their respective hydraulic motors to rotate, driving the pipes to rotate the axis and move along the axial direction. Change the rotation direction of the hydraulic motor to change the rotation direction and axial movement direction of the pipe to achieve reversible straight straight. Then send the tube to the straight tube to the material rack through the unexpected device on the other end. For pipes with large local bending and deformed, you can use the punch at both ends to perform local straight straight, and then overall straight.
