Product Overview：
Large-diameter seamless steel pipes can be categorized into hot-rolled large-diameter seamless steel pipes and hot-expanded large-diameter seamless steel pipes. Hot-expanded seamless steel pipes, also known as hot-expanded tubes, typically range in size from 325mm to 1220mm and can be up to 120mm thick. They are steel pipes with low density but strong contractility, produced through a manufacturing process that utilizes the cross-rolling or drawing method to expand the diameter of the raw tube. Hot-rolled seamless steel pipes undergo no specialized heat treatment after hot rolling and are directly delivered after cooling, known as the hot-rolled condition. The termination temperature for this condition is generally between 800-900℃, followed by natural cooling in air, making the hot-rolled condition equivalent to normalizing treatment.
Product Process：
Qualified round tube billets undergo heating and piercing → hot rolling and hole expansion → rough and finish rolling and forming → tempering heat treatment → degreasing and derusting → straightening and cutting to length; for hydraulic high-pressure pipes, additional processes such as internal wall honing and cleaning are added, followed by hydrostatic testing, nondestructive testing, and rust prevention treatment.
| Product List |
| Product Name: | Hot-rolled large-diameter seamless steel pipe | Seamless pipe |
| Product Name: | Hot expanded seamless steel pipe | Seamless pipe |
| Product Name: | 10# large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 20# large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 45# large-diameter seamless steel pipe | seamless pipe |
| Product Name: | Q235 large-diameter seamless steel pipe | seamless pipe |
| Product Name: | Q345 large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 16Mn large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 40Cr large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 27SiMn large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 12Cr1MoV large-diameter seamless steel pipe | seamless pipe |
| Product Name: | 15CrMo large-diameter seamless steel pipe | seamless pipe |
| Parameter range |
| Outer diameter | Φ220mm-Φ630mm |
| Wall thickness | 6mm-80mm |
| Standard length | 1-12m, customizable length available |
| Outer diameter accuracy | Maximum ±0.05mm |
| Non-standard customization | Support for special wall thickness, inner hole honing, and irregular size processing |
Optional tolerance range |
| Tolerance control | Optional manufacturing process |
| Tolerance ≤ 0.05 mm | Cold rolling |
| Tolerance ≤ 0.10 mm | Cold rolling |
| Tolerance ≤ 0.30 mm | Cold drawing | Cold rolling |
| Tolerance ≤ 0.50 mm | Cold drawing | Hot rolling |
| Tolerance ≤ 1.00 mm | Hot rolling | Hot expanding |
Optional delivery status
|
| Oil removal from oil pipes | Annealing and straightening | Steel pipe corrosion prevention |
| Steel pipe threading | Length cut-to-length | Steel pipe coating |
| Steel pipe cap | Exquisite bundling | Beveling |
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