The pressure water transmission channels in the water diversion system of hydropower stations generally take the form of water transmission tunnels, reinforced concrete culverts or steel pipes. Among them, the use of steel pipes occupies an important position, and among the types of steel pipes, SSAW steel pipes are the most common. In the past, the pressure steel pipes used in hydropower stations were mostly straight-seam steel pipes rolled by manufacturers according to design drawings. Its design and manufacturing meet the requirements of the Design Specifications for Pressure Steel Pipes for Hydropower Stations. However, the processing cycle of straight seam steel pipes is long, the cost is high, and the quality of welding and forming is not good, especially in projects with high water heads, long pipelines, and small diameters. This problem can be solved if the pressure steel pipe is mechanized and mass-produced. SSAW steel pipe can solve the above problems. Spiral seam steel pipes are produced by specialized manufacturers with streamlined operations and high quality welding and forming. There are many SSAW steel pipe manufacturers with large production capacity and low production costs. In the past, spiral seam steel pipes were widely used in water supply and drainage, petrochemical industry, heating pipe network, gas and coal gas industries. Now they are widely used in hydropower stations. However, there are issues worthy of study in the stress analysis of spiral seam steel pipes.
Because for the entire pipe body, due to differences in welding materials and welding quality, the weld is the weakest part. Therefore, when calculating the strength of pressure steel pipes, the weld is usually used as the calculation point for strength calculation. Generally speaking, there are several types of loads on pressure steel pipes: axial force; normal force; radial force; vertical and horizontal force, etc. However, the axial force and radial force caused by water pressure play a major role in the strength of the pressure steel pipe. For the convenience of analyzing the problem, we only take the axial force and the radial force to analyze the problem.
analysis.
1. Production status of spiral seam steel pipes
At present, there are many manufacturers producing spiral seam steel pipes in China, with strong production capacity. The product series is relatively complete. The nominal diameter of steel pipes ranges from 300 to 2500mm; the wall thickness ranges from 6 to 22mm. The materials include ordinary carbon structure, low alloy structural steel and high-strength alloy steel. It can also be processed according to user requirements. steel
2. The manufacturing process of spiral seam steel pipe. The spiral seam steel pipe uses an automatic spiral seam double submerged arc welding unit, which is composed of a shearing, flat head, hydrostatic testing machine, conveyor and beveling machine to form a production line.
The process flow is as follows;
Raw material inspection ~ uncoiling ~ initial straightening ~ cutting butt welding ~ fine straightening ~ milling ~ delivery ~ forming, internal and external welding ~ weld beads, external inspection ~ automatic repair welding, X-ray inspection, film taking and manual ultrasonic flaw detection and re-inspection ~ tube end
Bevel processing ~ hydrostatic pressure test ~ automatic length measurement, weighing ~ coating, marking ~ warehousing. Spiral seam double submerged arc welded steel pipe is made of strip steel formed at room temperature and continuously welded. It has undergone strict physical and chemical inspection, non-destructive testing, hydraulic test and other testing methods. The product is organized and produced according to standards. The spiral seam double submerged arc welded steel pipe is The quality standards of submerged arc welded steel pipes meet the requirements of D5017-93 standard. "Conveyor Steel Pipe" is a product standard, and its quality meets the requirements of "Specifications for Manufacturing, Installation and Acceptance of Pressure Steel Pipes" D 5017-93.
The commonly used steel materials for spiral seam steel pipes include Chinese standard carbon structural steel series, low alloy structural steel series, and in recent years, international standard pipeline steel series. Users have a wide range of choices.
Advantages of spiral seam steel pipes used in water diversion systems of hydropower stations
Spiral seam steel pipes are suitable for hydropower station water diversion systems with long pipelines, small and medium diameters, and high water heads. Its advantages are fast manufacturing, good welding quality, good forming, and low cost. It is a pipe type worthy of promotion and application in the water diversion system of hydropower stations.
To learn more, please visit the website:
www.baowi-steel.com