Views: 783 Author: Site Editor Publish Time: 2022-08-19 Origin: Site
In recent years, using hot-rolled coils as raw materials, the process of HFW high-frequency welding + thermal tension reduction + full tube body heat treatment has been widely used to produce high-precision, high-grade steel casings. In production applications, it is found that the quality of hot-rolled coils directly affects the forming quality, unit operation rate and yield of HFW welded pipes.
Therefore, by analyzing the influencing factors of the quality of the hot-rolled coil, and then improving the smelting, rolling and slitting and other processes to control the quality of the hot-rolled coil, it can provide a good guarantee for the forming and welding of the welded pipe.
Four directions:
(1) Reasonable design of the chemical composition of the coil, through the improvement of the smelting and rolling process, reducing the band structure, reducing the inclusions, and improving the purity of the raw materials, can effectively improve the weldability and comprehensive performance of the HFW welded pipe.
(2) Precise control of the geometrical dimensional accuracy of the coiled plate from the process of coil rolling, slitting and edge milling can provide a guarantee for the precise forming and stable welding of the tube blank, and at the same time, it is beneficial to improve the geometrical accuracy of the final product.
(3) By optimizing the hot rolling process and equipment, controlling the appearance defects such as camber bend, tower shape, wave bend, pit, scratch, etc., can effectively improve the forming and welding quality of HFW welded pipe, and improve the yield.
(4) Through the optimization of the slitting process, the coiled plate can obtain good section quality, and at the same time, the optimal uncoiling method can be selected during feeding, which can create good conditions for HFW welded pipe forming and welding and weld bead burr removal.
The appearance of gaps refers to the phenomenon that the welds are not bonded together. The length of the gaps is generally more than a few centimeters or even longer. The main reasons are as follows:(1) Pass wearAs the extrusion roll hole pattern wears, the hole pattern (R) size gradually becomes l
Sand-hole pipes are also a kind of quality accident caused by weld leakage, but their gaps are very small, some of them cannot be directly observed by human eyes, and must be found through testing equipment, so we call this kind of pipes sand-hole pipes. The main reasons for sand hole pipes are as f
(1) The hole type does not matchThere are two-roller, three-roller and four-roller weld seam extrusion structures. As long as the combined hole shapes do not match, it is easy to cause scratches on the surface of the tube blank, especially the two-roller structure.There are many factors that cause t