Forming Situation effect the quality of the welded steel pipe

n high frequency straight seam welded steel pipe production, the tube billet forming joint condition directly affects the quality of the weld, during which the butt welding joint surface parallel degree is particularly important. In the process of steel tube joint welding, first through the adjustment quantity of the roller on the roller and the gap between the top roller to ensure that the parallel degree of joint. Welding of kneading roller pass characteristics of kneading rack up roller pass radius around 10% larger than other kneading roller, thus, kneading roller on the outside of the roll surface with steel tube aspirations of circular cross section, the gap between the gap is commonly known as "followed by the gap". In the actual forming, steel pipe section may be ambitious round. Usually, due to inadequate deformation of strip steel edge, section simple peach shape, if do not adjust it will constitute welding joint surface is not parallel to the docking, serious affect weld quality.

If the kneading roller and other kneading roller chooses the same radius of groove, when after adjusting the quantity of the kneading roller to eliminate the v-shaped joint, the outer edge of the roller roller surface will be strong pressure on the steel pipe appearance, simple tube surface scars, and pose a serious V joint. Set, thus "followed by the gap" is based on the actual characteristics of tube billet forming, after adjusting quantity of the roller to effectively eliminate V joint. Kneading roller on the way to adjust in accordance with the specifications set groove roller bearing, if discover forming joint is V, can be within the scope of the "followed by the gap", on the quantity of the kneading roller to adjust. On the limit of the quantity of the kneading roller is kneading roller outer roller surface on the mild steel pipe appearance constitute a shallow indentation. According to experience, when arrived at the pressure limit, even a high strength steel tubes, generally can also constitutes a forming joint parallel (I). In the use of the experience, must be strictly in accordance with the planning values to set the gap between the two on the roller. The gap change will directly lead to "followed by the gap". If each roll change when not strictly according to the planning value set, the gap then pass adjustment reproducibility is difficult to realize. For the same reason, in the asymmetric adjustment to eliminate roll on the right side, must only to adjust work station on the side of the roller, and let the other side of the top roller is fixed as the benchmark. If adjust both sides on the roller, may make the roll gap gradually away from the set point.