Year1
- 材质：
- Q235B
- 规格：
- 630*12,630*16,325*9,1820*18,1620*20,2020*18
- 质量等级：
- 正品（受质量异议）
General material,
Brief description
Large-diameter spiral steel pipe is a general term, generally referring to spiral steel pipes with a diameter greater than one meter. Spiral steel pipes are made of steel strips that are bent and then welded. Steel pipes need to undergo hydraulic pressure, bending, flattening and other experiments, and have certain requirements for surface quality. The delivery length is usually meters, and delivery to fixed length is often required. The specifications of spiral steel pipes are expressed in nominal diameter (mm). The nominal diameter is different from the actual diameter. According to the specified wall thickness, there are two types: ordinary steel pipes and thickened steel pipes.
Material
Commonly used materials in China are,
Purpose
Spiral steel pipe is mainly used in water supply projects, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, and urban construction. It was developed in my country One of the twenty key products. Used for water supply and drainage for liquid transportation. For gas transportation, coal gas, steam, and liquefied petroleum gas are used. It is used as piling pipes for structures, pipes for bridges, wharves, roads, building structures, etc.
Submerged arc welding process
The spiral steel pipe welding method is the submerged arc welding forming process, and the forward swing-type intermittent production unit speeds up the welding speed. The unit consists of uncoiler, straightening machine, centering device, hydraulic shear, milling and welding machine, disc shear, edge milling machine, board cleaning equipment, delivery machine, board edge pre-bending equipment, forming machine, internal welding, external welding, It consists of flashing, pulling out, slag dumping, repair welding, flat head chamfering, hydraulic inspection, finished product inspection, and oil removal collection. The whole process of submerged arc welding of spiral steel pipe is as follows
Principle of submerged arc welding of spiral steel pipe Submerged arc welding uses arc heat energy for welding. The difference from manual arc welding is that the wire of submerged arc welding is exposed and there is no For paint and submerged arc welding, the flux is laid in advance on the place to be welded. The submerged arc welding wire extends into the flux, and the arc burns under the flux. The welding wire is in contact with the workpiece. After pressing the start button, the moment the welding wire and the workpiece are energized, the welding wire is withdrawn, the arc ignites, the welding car moves forward, and the welding wire is continuously transported downward to maintain the arc burning under the flux layer. A welding pool is formed. Around the arc, the flux melts to form a cavity. This cavity and molten pool continue to advance, while the metal behind the molten pool solidifies, forming a continuous weld. Since this process is carried out under flux, we cannot see it with the naked eye. Visible with the aid of radiography.
The spiral steel pipe adopts submerged arc automatic welding welding technology. In addition to high production efficiency and less production auxiliary time, it saves the time of changing welding rods. The welding conditions are clean and spatter-free, saving the time of cleaning. The weld quality is high. It also provides necessary conditions for the delivery of spiral steel pipe factories, ensuring the production time of large-volume spiral steel pipes, so it is still widely used.
Spiral seam submerged arc welded steel pipe is made by bending the strip steel in a spiral shape, and using automatic submerged arc welding to weld the inner seam and outer seam to make a spiral seam steel pipe. It can be widely used in the production of large-diameter steel pipes for the following reasons
As long as the forming angle is changed, steel pipes of various diameters can be produced from strip steel of the same width
Because it is continuously bent and formed, the steel pipe The fixed length is not limited
The welds are spirally distributed evenly on the entire circumference of the steel pipe, so the steel pipe has high dimensional accuracy and high strength
The equipment cost is cheap, and it is easy to change the size, suitable for small Production of batches and multiple varieties of steel pipes.
Types of welds
Types of welds for large diameter spiral steel pipes
Welding seams are circular welds formed by joining two steel pipes together.
Butt welding seam is a welding seam where the steel plate or steel strip on the spiral seam steel pipe is connected head to tail.
Bit welding is a weld used to fix the butt edges before final welding.
Surface requirements for welds of caliber spiral steel pipes
The shape of welds of caliber spiral steel pipes should be uniform and regular, with gentle transitions. The surface of the welds should be free of arc breaks, burn-throughs, cracks, scars, folds, arc craters and other defects. .
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