Study On Forming Control Technology Of Spiral Welded Pipe

With the constant development and construction of oil and gas transmission pipeline, welded pipes constantly develop the level of large-diameter, thick-wall thickness and high-grade. Due to the characteristics of SAWH’s low investment, light weight of manufacturing equipment, high production efficiency, small width of strip steel etc., it has become the basic type of oil and gas transmission line pipe at home and abroad, which makes hundreds of tons large-diameter pipeline production depend on domestic market. And it saves project cost and makes significant contribution to the development of Chinese pipeline industry..The present paper according to production situation of the Shengli Steel Pipe CO.,LTD,, makes a research on the relation between SAWH forming parameters and forming quality and analyses SAWH’s advantage and disadvantage and spiral forming’s effect on pipe quality (It is mainly welding seam quality and appearance quality).This paper make an emphasis on the research of the specific problems during the process of spiral forming, analyses various elements that affect the stability of spiral forming and proposes the solution that is applied successfully in practice. The reasonable adjustment of forming machine is the premise of guaranteeing forming quality. It refers to the principle and specific methods of adjusting forming machine as per the product, analyses three kinds of forming rollers’characteristics, proposes reasonable forming rollers’outline drawing, analyses the effect on the pipe production caused by strip steel’s quality defect and proposes the attentions during the process of selecting materials; in the practical production, selecting reasonable SAWH forming angle, optimizing the space between 1# and 3# roll and selecting reasonable forming rolling reduction can improve the stability of SAWH forming. The paper put forwards the effective control measures focus on the exceeding diameter’s tolerance, peaking, offset and other defects, analyses the degree of spiral forming deformation and the relation between elasticity recovery amount and residual stress. It has built the relational model of 2# roll rolling reduction and residual stress through analyzing the deflection differential equation that describing the situation of plate in the forming process.In this paper, the author has carried out the production verification in various aspects, such as the various aspects of the adjustment measures, the parameters optimization on the control measures and the residual stress.