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 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 |
| Executive Standards | ASTM A106, API 5L, DIN 17175, GB/T 8163 |
| Non-standard customization | Support for special wall thickness, inner hole honing, and irregular size processing |
| High frequency specifications in stock (outer diameter x commonly used wall thickness mm) |
Outer diameter (mm) | 219
| 245 | 273 | 299 | 325 | 351 | 377 | 402 |
| Standing wall thickness (mm) | 6、7、8、10、12、14 | 6、8、10、12、14、16 | 7、8,、10、 12、14、16、18 | 8、10、12、14、16、 20 | 8、10、12、14、16、18、20 | 8、10、12、14、16、 20 | 9、10、12、14、 16、18、20、25 | 10、12、14、16、20、25 |
| Corresponding nominal diameter DN | DN200 | - | DN250 | - | DN300 | - | DN350 | - |
Outer diameter (mm) | 426 | 450 | 480 | 508 | 530 | 560 | 610 | 630 |
| Standing wall thickness (mm) | 10、12、14、16、18、20、22、25、30 | 10、12、14、16、 20、25 | 10、12、14、16、 20、25、30 | 12、14、16、20、25、30 | 12、14、16、18、20、25、30 | 12、14、16、20、25、30 | 12、14、16、20、25、 30 | 12、14、16、18、20、 25、30、35 |
| Corresponding nominal diameter DN | DN400 | - | - | DN450 | DNS00 | - | DN600 | - |
| Industry standard: Outer diameter ≥ 219mm is considered as large-diameter seamless pipe; Dimensional standard national standard: GB/T17395 |
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 |
| Allowable deviation of outer diameter |
| Accuracy class | Normal level (default) | Higher level (specified in the contract) |
| Allowable deviation | ± 1% D or ± 0.5mm, whichever is greater | ± 0.75% D or ± 0.3mm, whichever is greater |
| Applicable process | Hot rolling and expansion | Hot rolling and expansion |
| Common outer diameter actual tolerance |
Outer diameter (mm) | 219
| 273 | 325 | 377 | 426 | 530 | 630 |
| Ordinary level tolerance (mm) | ±2.19 | ±2.73 | ±3.25 | ±3.77 | ±4.26 | ±5.30 | ±6.30 |
Qualified range (mm) | 216.81~221.19 | 270.27~275.73 | 321.75~328.25 | 373.23~ 380.77 | 421.74~430.26 | 524.70~535.30 | 623.70~636.30 |
| Allowable deviation of wall thickness for hot-rolled large-diameter steel pipes (D>102mm) |
| S/D (wall thickness/outer diameter) | ≤0.05 | 0.05～0.10 | ＞0.10 |
| Allowable deviation | ± 15% S or ± 0.4mm, whichever is greater | ± 12.5% S or ± 0.4mm, whichever is greater | +12.5%S/-10%S |
| Allowable deviation of wall thickness for hot expanded diameter steel pipes (219-630mm mainstream) |
| Project | Wall thickness |
| Allowable deviation | +17.5%S / −12.5%S |
| Actual tolerance of commonly used wall thickness |
| Wall thickness S (mm) | 8
| 10 | 12 | 14 | 16 | 20 | 25 | 30 |
| Upper deviation (mm) | +1.40 | +1.75 | +2.10 | +2.45 | +2.80 | +3.50 | +4.38 | +5.25 |
| Lower deviation (mm) | -1.00 | -1.25 | -1.50 | -1.75 | -2.00 | -2.00 | -3.13 | -3.75 |
| Qualified range (mm) | 7.00~9.40 | 8.75~11.75 | 10.50~14.10 | 12.25 ~ 16.45 | 14.00 ~18.80 | 17.50~23.50 | 21.87~29.38 | 26.25 ~ 35.25 |
| Curvature (straightness) |
| Wall thickness conditions | S ≤ 15mm | S ＞ 15mm |
| Bending degree per meter | ≤1.5 mm/m | ≤2.0 mm/m |
| Full length curvature | ≤ Total length × 0.15% | ≤ Total length × 0.15% |
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 |
Now ready to place an order:
You can view Ordering Matters | Payment Matters, or enter Submit Purchase | Contact Us
Jia hui
Jia hui