Straightness is an crucial indicator of the top quality of HFW seamless steel tubes. The increased the straightness, the easier it is to ensure the thread high quality of the oil effectively pipe, and it also facilitates subsequent processing and inspection. In manufacturing, the factors for the excessive straightness of HFW steel pipes (such as large-frequency electrical resistance welded pipes) are as follows:
* Improper adjustment of the straightening frame: The HFW seamless steel pipe bends out from the sizing unit and is bent in 1 path.Answer: In the HFW straightening, the Turkish head is employed to modify the straightness. Appropriate adjustment of the deflection of the Turkish head reverse bending is the key to controlling the bending of the HFW steel pipe. For the bending brought on by improper adjustment of the straightening frame, the operator must keep the Turkish head frame adjacent to the flying noticed fixed, and adjust the other Turkish head in the opposite direction according to the bending path.
* The unevenness of the coil is not serious: the bending phenomenon of the steel pipe is critical, and the bending course of the steel pipe is not one course.Solution: For bending due to uneven strength of the coil, it must be solved by the coiling mill by increasing its rolling degree. The difference in power between the coils should be managed inside of thirty MPa.
* The temperature of the upper and reduced surfaces of the steel pipe is uneven: the seamless steel pipe in manufacturing is straight right after cutting, but it is bent when cooling on the finishing stand, and the overall bending direction of the steel pipe is the identical.Resolution: Renovate the water cooling gadget so that the sum of cooling water on the upper surface can be controlled to maintain the temperature of the upper and decrease surfaces of the steel pipe the very same. For large diameter steel pipes, when the water cooling cooling water volume is maximized, the upper surface temperature is nevertheless higher than the reduced surface, which can be appropriately diminished. The pace of the manufacturing line, or the installation of the coolant water tower, accelerates the cooling of the coolant the reverse adjustment technique is adopted, that is, in accordance to the course and extent of the bending of the steel pipe on the finishing gantry, the reverse adjustment is manufactured throughout the sizing straightening.
* Insufficient sizing quantity: The steel pipe is straight just before the hydrostatic pressure check, but the bending phenomenon occurs right after the hydrostatic pressure check, and the bending course is fixed.Solution: By appropriately rising the sizing amount and reducing the excessive residual pressure of the HFW steel pipe, the bending phenomenon can be avoided. If the sizing sum is elevated, the bending phenomenon is still not eliminated, and additional adjustment of the forming hole shape is necessary. The sheet has an further deformation sum to compensate for the rebound right after deformation, decrease residual pressure, and lastly solve the bending problem of the steel tube. site
