What are the forming methods of welded steel pipes?

Welded pipe, also known as welded steel pipe, is basically made of steel plates or steel strips that are curled and welded. The production process of welded steel pipes is simple, the production efficiency is high, there are many varieties and specifications, and less equipment, but its general strength is lower than that of seamless steel pipes. Since the 1930s, with the rapid development of high-quality strip rolling production and the advancement of welding inspection technology, the quality of welds has continued to improve, the varieties and specifications of welded steel pipes have increased, and seamless steel pipes have been used in more and more fields. replaced. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the weld form.

1. Single radius forming method of welded steel pipe

There are three single-radius roll forming methods: circumferential bending forming method, edge bending forming method and center bending forming method. The single-radius forming method is that the pass shape consists of a single radius. The horizontal rollers and vertical rollers of the forming machine are alternately arranged. The strip passes between the horizontal rollers and the vertical rollers, and the flat plate is gradually bent into a round tube.

2. Welded steel pipe circumferential bending forming method

The strip is bent and deformed simultaneously in the entire width direction, and the bending radius of each frame gradually decreases; the bending forming method starts from the edge of the strip, with the bending radius unchanged, gradually increasing the deformation angle, and reducing the width of the middle part of the strip until the strip is The steel becomes rounded and closed; the center bending forming method starts from the center of the strip and gradually expands to the edges on both sides with a constant bending radius until it becomes round and closed.

3. Welded steel pipe double radius forming method (comprehensive bending forming method)

Combined deformation uses more than two basic deformation methods, but the edge forming method + circumferential forming method is widely used. The forming method of comprehensive deformation of the edge and circumference of the tube blank uses the hole radius of the extrusion roller or the radius of the finished tube as the edge bending radius to bend the edge of the steel strip to a certain deformation angle, which remains basically unchanged in each subsequent forming stage. , and the bending forming in the middle part of the steel strip is distributed according to the circumferential bending forming method. The forming process of this method is stable, the deformation is uniform, the relative elongation of the edge is small, and the forming quality is good.

Application scope of welded steel pipe:

Welded steel pipe products are widely used in boilers, automobiles, ships and buildings, light structural door and window steel and furniture, various agricultural machinery, scaffolding, wire pipes, high-rise shelves, containers, etc. All can meet customer requirements, and special welded pipes can be processed according to customer requirements.

Furnace welded pipe: Can be used as water and gas pipelines, etc. , while large-diameter straight seam welded pipes are used for high-pressure oil and gas transportation, etc., while spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc.

Spiral welded pipe: Generally speaking, its strength is higher than that of straight welded pipe. It can not only produce welded pipes with larger diameters from narrow pipe blanks, but also can produce welded pipes with different diameters from pipe blanks of the same width.