The production process of thick-walled seamless steel pipes

The production process of thick-walled seamless steel pipes seems professional, but it is not difficult to understand! Many friends often encounter these troubles when purchasing or using: insufficient strength of steel pipes, rough inner walls, long delivery cycles, and even cost surges due to improper process selection. Don't worry, today we will start from the actual pain points and disassemble the four core production processes in the most down-to-earth way to help you avoid pitfalls easily!

1. Hot rolling method (hot extrusion)

Pain point: Traditional processes are inefficient and dimensional accuracy is difficult to control

This is the most classic method, just like "kneading dough"-the heated red steel billet is hollowed out with a piercer, and then repeatedly rolled and formed by a tube rolling machine. The advantage is that it can produce ultra-large diameter steel pipes (up to 650mm!), but the surface is prone to oxide scale and requires additional polishing. Suitable for "rough" scenes such as thermal power generation and oil pipelines.

2. Cold drawing method

Pain point: thin-walled tubes are easy to deform and the processing cost is high

Take the hot-rolled steel pipe as "plasticine" and use a mold to hard-draw it at room temperature. Just like making hand-pulled noodles, the diameter shrinks a little with each pull. The surface of the steel pipe is as smooth as a mirror, and the size is accurate to the level of hair (±0.05mm). Medical equipment and precision instruments love to be used. But be careful thin wall thickness may be torn!

3. Cold rolling method

Pain point: large equipment investment, small batch production is not cost-effective

It is equivalent to doing "SPA" for steel pipes: using a tapered mandrel to rotate and roll at the same time, and the whole process is like twisting a towel. The biggest highlight is that it can produce ultra-thick wall steel pipes (wall thickness of more than 100mm!), and the metal fiber is denser. The high-pressure reactor of chemical equipment and the sealed shell of nuclear power plants rely on it to support the scene. However, the production line costs hundreds of millions, which is suitable for local tyrants.

4. Spinning method

Pain point: It is difficult to process special-shaped pipes

This is a new "black technology" that allows steel pipes to be shaped by rotation like pottery. It is particularly suitable for manufacturing "high-end products" such as rocket engine casings and special-shaped military pipe fittings. The advantage is that it can achieve operations such as changing diameters and wall thicknesses, but the craftsmanship of the master directly determines the quality of the finished product. At present, there are no more than 10 manufacturers in China that have mastered the core technology.