Seamless Steel Pipe
Introduction
Seamless steel pipe is a hollow steel made by perforating and rolling solid steel billet. There is no welding process in the whole process, including hot-rolled seamless steel pipe and cold-rolled seamless steel pipe. It is widely used in various fields because of its characteristics of no welds, high strength and pressure resistance, and wide applicability.
Table of Contents
- Seamless Steel Pipe Specifications
- Seamless Steel Pipe Application
- Seamless Steel Pipe Manufacturing Process
- Features of Seamless Steel Pipe
- Hot-rolled Seamless Steel Pipe vs Cold-drawn Seamless Steel Pipe
- Calculation of Seamless Steel Pipe Weight
- Why Choose Us

Seamless Steel Pipe Specifications
Product Name | Seamless Steel Pipe |
Outer Diameter | 6mm – 1200mm |
Wall Thickness | 2.5mm – 100mm |
Length | 2m, 3m, 6m, 9m, 12m or cut according to customer requirements |
Material | Carbon steel (Q345, 20#, 45#), stainless steel (304, 316), etc. |
Standard | GB/T, ASTM, API, DIN, JIS, etc. |
Surface State | Pickling (removing oxide scale), cold drawing (bright surface), galvanizing (anti-corrosion), etc. |
Shape | round tube, square tube, rectangular tube, special-shaped tube |
Technology | Hot rolling, cold drawing |
Processing Service | Welding, punching, cutting, etc. |
MOQ | 5 Tons |
Packing | Standard export packing or as required |
Seamless Steel Pipe Application
- Oil/gas: drill pipe, casing, oil pipeline, cracking furnace pipe, hydrogenation reactor pipe, etc.
- Chemical equipment: reactor, heat exchanger pipe, corrosion-resistant pipe, etc.
- Power industry: high-pressure boiler pipe, superheater pipe, high-pressure steam pipe, power station pipe, etc.
- Machinery manufacturing: hydraulic cylinder, bearing, transmission shaft, exhaust pipe, precision instrument pipe, automobile gearbox gear shaft, etc.
- Building structure: steel structure pillar, bridge load-bearing components, curtain wall support frame (special-shaped pipe such as square pipe), medium and low pressure transmission pipeline for municipal water supply/heating.
- Metallurgical and mining industry: high-pressure oil pipes and wear-resistant conveying pipes for mining machinery, cooling water pipes and high-temperature flue gas pipes in metallurgical equipment.


Seamless Steel Pipe Manufacturing Process
- The core process of hot-rolled seamless steel pipe: heating of tube billet → perforation → rolling → sizing → cooling → finishing
- The core process of cold-drawn seamless steel pipe: tube billet preparation → pickling → cold rolling (cold drawing) → heat treatment → finishing
Production Video
Features of Seamless Steel Pipe
- No welds, high strength: The entire pipe is formed in one piece, without welds, so it can withstand higher pressure and impact, avoiding the risk of cracking.
- Various sizes, strong adaptability: The diameter and thickness range of seamless steel pipes are relatively wide, which can meet the needs of various scenarios.
- Controllable precision: Especially the seamless steel pipes produced by cold drawing process, the size error is very small, the surface is smooth, and it is suitable for scenes with high precision requirements.
- Resistant to heat and pressure, suitable for extreme environments: It can adapt to complex environments such as high temperature (such as boiler pipes), low temperature (such as refrigeration equipment) and corrosion (chemical pipelines).



Hot-rolled Seamless Steel Pipe vs Cold-drawn Seamless Steel Pipe
Comparison items | Hot-rolled seamless steel pipe | Cold drawn seamless steel pipe |
Production process | High temperature perforation + hot rolling forming | Hot rolled tube + cold drawing/cold rolling finishing |
Temperature | 1200℃ high temperature processing | Normal temperature processing |
Surface quality | With oxide scale (need pickling) | Smooth surface (can be used directly) |
Dimensional accuracy | Low (±0.5mm) | High precision (±0.05mm) |
Wall thickness uniformity | General | Extremely uniform |
Mechanical properties | Low strength | Strength increased by more than 30% (cold work hardening) |
Production cost | Low | High (multiple finishing) |
Production speed | Fast (suitable for large quantities, large pipes, thick-walled pipes) | Slow (suitable for small batches, small tubes, precision tubes) |
Typical specifications | Φ25-1200mm | Φ6-160mm |
Main uses | Oil pipeline/building structure | Hydraulic cylinder/precision mechanical parts |
Calculation of Seamless Steel Pipe Weight
1. Calculation formula for round steel pipe weight
Weight (kg/m) = (outer diameter – wall thickness) × wall thickness × coefficient
- Carbon steel: coefficient is 0.02466 (density 7.85g/cm³)
- Stainless steel: coefficient is 0.02491 (density 7.93g/cm³)
2. Calculation formula for square steel pipe weight
Weight (kg/m) = (side length × 4 – wall thickness × 4) × wall thickness × 0.00793
3. Calculation formula for rectangular pipe weight
Weight (kg/m) = [(length + width) × 2 – wall thickness × 4] × wall thickness × 0.00793
In order to provide convenience to customers, we provide a metal pipe weight calculator, you can enter our metal pipe weight calculator page for calculation.


Why Choose Us
- Excellent quality: Select high-quality steel billets, use advanced hot rolling/cold drawing technology, and conduct quality inspection throughout the entire process to ensure no defects and stable mechanical properties.
- Complete specifications: Covering 6mm-1200mm outer diameter, wall thickness 0.5mm-100mm, carbon steel, stainless steel and other materials are complete, and special-shaped pipes are supported.
- Efficient delivery: With high-capacity production lines, regular specifications are in sufficient stock, and value-added services such as cutting, straightening, and surface treatment can be provided to shorten the delivery cycle.
- Complete qualifications: Passed ISO 9001 and ISO 14001 certifications, with a mature supply chain system, services cover global customers, and worry-free from order to after-sales.
Wanzhi Steel is a leading steel pipe supplier in China. In addition to seamless steel pipes, it also supplies spiral welded pipes, straight seam welded pipes, and stainless steel pipes. With 17+ years of production experience and 14+ years of export experience, we can provide you with the best solution.
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CONTACT US
- Mobile: +8617637100809
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- Email: info02@wanzhisteel.com
- Address: 10F, Building B, Erqi Center, Erqi District, Zhengzhou City, Henan Province, China