Research On Feasibility And Manufacturing Technique Of Heating Bending SSAW Pipeline

Bends are the important parts in the long distance pipeline of oil and gas. Longdistance pipeline of oil and gas will go through many regions of complex landformand villainous climate. So when tubing many bends of large caliber will be used.Bends have complex stress in use. Bends are difficult in technology in the course ofbending and have many factors of affecting quality ability. The manufacture andquality of bends affect directly on the security and reliability and economic effect ofinvestment. Now our country is facing several large pipeline. As the principalcompany of pipeline engineering, CNPC is taking on the zhongxian-wuhan pipeline,and will take international pipelines. In all the engineering SSAW pipeline will beused. So CNPC decides to research on the technique of heating bending SSAWpipeline.In this paper the author analyses the speciality of strength in welded seam ofSSAW pipeline and theoretic feasibility of bending. The welded seam of SSAWpipeline has an angle with axis, and wards off the direction of major stress. So thetensile stress in welded seam of SSAW is much letter than that of UOE. The testingresult confirms that it is feasibility to bend SSAW pipeline using the technique ofheating bending UOE pipeline.In this paper the author studies the influencing factors and controlling factors ofheating bending of SSAW pipeline. By means of comparison of SSAW and UOEheating bending, the influencing factors and controlling factors of heating bending ofSSAW pipeline are: bending method, induction heating temperature, feeding speedand cooling speed.In the study of heating bending of SSAW pipeline, when heating temperature isin the range of 790~1020℃ and feeding speed is 0.72mm/min or 0.69mm/min, thetensile strength and hardness and impact work have a little change in the weldingseam. The tensile strength and hardness are lower a little and impact work increases alittle.