Large-diameter steel pipes have won unanimous praise from consumers in use. They are widely used in mechanical parts, fluid transportation, construction sites, etc. Large-diameter steel pipes have undergone strict inspections during manufacturing, which has also improved their durability. Large-diameter steel pipes have high dimensional accuracy and smooth surface finish inside and outside the pipe. There is no oxide film on the inner and outer surfaces of the steel pipe after heat treatment. The steel pipe has no cracks when expanded and flattened, and no deformation when cold bent. It can withstand high pressure and can be subjected to various complex deformations and mechanical deep processing.
Expression of large diameter steel pipe diameter:
1. For water-gas transmission steel pipe (galvanized or non-galvanized), cast iron pipe, and other pipes, the pipe diameter should be expressed in nominal diameter DN;
2. For seamless steel pipe, welded steel pipe (straight seam or spiral seam), copper pipe, stainless steel pipe, and other pipes, the pipe diameter should be expressed in outer diameter × wall thickness;
3. For reinforced concrete (or concrete) pipe, clay pipe, acid-resistant ceramic pipe, tile pipe, and other pipes, the pipe diameter should be expressed in inner diameter d;
4. For plastic pipes, the pipe diameter should be expressed in accordance with the product standard method;
5. When the design uses nominal diameter DN to express the pipe diameter, there should be a comparison table of nominal diameter DN and corresponding product specifications.
The specifications of rigid polyvinyl chloride pipes for building drainage are expressed in de (nominal outer diameter) × e (nominal wall thickness) (GB5836.1-92)
The specifications of polypropylene (PP) pipes for water supply are expressed in de × e (nominal outer diameter × wall thickness).
Processing methods of large-diameter steel pipe fittings:
The price of large-diameter steel pipe fittings is divided into forging, stamping, roller, rolling, bending, expansion, and other methods. Several processing methods are introduced as follows:
1. Bending method of large-diameter steel pipe fittings: There are three commonly used methods, one is called the stretching method, another method is called the stamping method, and the third roller method has 3-4 rollers, two fixed rollers, and one adjustment roller. Adjust the fixed roller spacing, and the finished pipe fittings are bent.
2. Stamping method of large-diameter steel pipe fittings: Use a tapered core on the punch press to expand the pipe end to the required size and shape.
3. Roller method of large-diameter steel pipe fittings: Place a core in the pipe, and use rollers to push the outer periphery for round-edge processing.
4. Forging method of large-diameter steel pipe fittings: Use a swaging machine to punch out the end or part of the steel pipe to reduce the outer diameter. Commonly used swaging machines are rotary, connecting rod, and roller.
5. Rolling method for large-diameter steel pipe fittings: generally no mandrel is used, suitable for the inner round edge of thick-walled pipes.
6. Bulging method for large-diameter steel pipe fittings: one method is to place rubber in the pipe and compress it with a punch to make the steel pipe bulge out; the other method is hydraulic bulging forming, filling liquid in the middle of the steel pipe, and the liquid pressure bulges the steel pipe into the required shape. Most of the production of corrugated pipes uses this method.
Post time: Apr-22-2025