Product Description

Seamless pipe is a hollow tubular steel without welding seams, which is made by perforated hot rolling, cold drawing or cold rolling process. It has the characteristics of uniform structure, high strength and good sealing. Its surface is usually the original color of metal (silver gray), and can be galvanized, painted, plated and other anti-corrosion treatments according to needs. According to the production process, it is divided into:

Hot-rolled seamless pipe: thick wall thickness, large outer diameter range, suitable for high pressure and high strength scenes;

Cold rolled / cold drawn seamless pipe: high precision, smooth surface, uniform wall thickness, mostly used for precision machinery or fluid transportation.

According to the material, it is divided into:
Carbon steel seamless pipe (such as Q235, 20# steel): low cost and wide application;
Alloy steel seamless pipe (such as 15CrMo, 42CrMo): high temperature, high pressure and corrosion resistance;
Stainless steel seamless pipe (such as 304, 316L): excellent corrosion resistance, suitable for food, medical, chemical and other fields.

Parameter

Standard Specification for Seamless Carbon Steel Pipe
Seamless Pipe, Mild Steel, Black Varnished and Hot-Dipped, Zinc-Coated (Galvanised)

ASTM A53/A53M Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless
Pipe ordered under this specification is intended for mechanical and pressure applications and is also acceptable for ordinary
uses in steam, water, gas, and air lines.

ASTM A106/A106M Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service
This specification 2 covers seamless carbon steel pipe for high-temperature service in NPS 1 ⁄ 8 to NPS 48 [DN 6 to DN 1200] inclusive, with nominal (average) wall thickness as given in ASME B 36.10M.

API SPECIFICATION 5L Specification for Line Pipe
This Standard specifies requirements for the manufacture of two product specification levels of seamless and welded steel pipes for use in pipeline transportation systems in the petroleum and 

natural gas industries

Our Hot Selling Sizes

Implementation standards

National standard: GB/T 8162 (for structure), GB/T 8163 (for fluid transportation), GB/T 3087 (for low and medium pressure boilers), GB/T 5310 (for high pressure boilers);
American standard: ASTM A106 (seamless steel pipe for high temperature), ASTM A312 (stainless steel seamless pipe);
European standard: EN 10216 (seamless steel pipe for pressure).

Applications

1. Industrial pipeline system
Fluid transportation: water, oil, gas (natural gas, steam) pipelines, such as municipal water supply, chemical raw material pipelines, thermal pipelines;
High-pressure scenarios: boiler pipelines (power station boilers, industrial boilers), hydraulic system pipelines (construction machinery, injection molding machines).
2. Machinery manufacturing
Structural support: automobile drive shafts, bicycle frames, oil drill pipes;
Precision parts: cylinder tubes, hydraulic cylinder barrels (high-precision cold-rolled seamless pipes are required).
3. Construction and Engineering
Steel structures: supporting columns of bridges and high-rise buildings (such as large-diameter hot-rolled seamless pipes);
Pile foundation engineering: steel pipes for piling, underground continuous wall pipes.
4. Chemical and Petroleum
Corrosive medium transportation: stainless steel seamless pipes are used to transport acid, alkali, and salt solutions;
Oil extraction: oil well pipes, casing (anti-sulfur and anti-corrosion alloy pipes are required).
5. Other fields
Shipbuilding: marine boiler pipes, seawater desalination pipes;
Medical equipment: stainless steel sterile pipes (pharmaceuticals, food processing);
Aerospace: aircraft engine oil pipes, hydraulic pipes (ultra-high strength alloy pipes are required).

Performance

1. Mechanical properties
High strength: seamless pipes have no welds, and the overall strength is higher than that of welded pipes, suitable for high pressure and impact loads;
Fatigue resistance: not easy to crack under cyclic loads, suitable for vibration environments (such as mechanical transmission pipes).
2. Corrosion resistance
Stainless steel material: 304/316L seamless pipes are resistant to acid, alkali and salt corrosion and are widely used in chemical and marine engineering;
Surface treatment: galvanizing (Zn), epoxy resin coating (EP), and polyethylene lining (PE) can further enhance the corrosion resistance.
3. Process performance
Weldability: Carbon steel and low alloy steel seamless pipes can be connected by welding, and stainless steel pipes require special welding materials;
Processability: Can be bent, expanded, reduced in diameter and other processing (cold-rolled pipes are easier to form).
4. Sealing
The weld-free design is suitable for scenarios with high sealing requirements (such as gas pipelines and hydraulic systems).

V. Packaging description
1. Conventional packaging
Small diameter pipes (outer diameter ≤108mm):
Bundled (50-200 pieces per bundle), fixed with steel or plastic belts;
Plastic protective caps are placed on the ends to prevent damage from bumps.
Large diameter pipe (outer diameter > 108mm):
Single or multiple pipes are packed in containers and wrapped with straw ropes or bubble film to prevent scratches;
Put them in wooden boxes or iron frames during long-distance transportation to prevent rolling.
2. Special protective packaging
Anti-corrosion requirements: The surface of stainless steel pipes is coated with anti-rust oil and wrapped with waterproof paper;
Precision pipes: Cold-rolled precision pipes are sealed with nylon bags to avoid dust pollution.
3. Labels
Each bundle/each pipe body is printed with: material, specification (outer diameter × wall thickness), implementation standard, production batch number, factory logo;
Outer packaging indicates: net weight, gross weight, destination, moisture-proof/anti-fall logo.

Customer Questions and Answers

1. Q: What is the difference between seamless pipes and welded pipes?
A:Structure: Seamless pipes have no welds, and welded pipes have longitudinal or spiral welds;
Strength: Seamless pipes have higher overall strength and are suitable for high-pressure scenarios (such as boilers and hydraulic systems);
Cost: The production process of seamless pipes is complex, and the price is 10%-30% higher than that of welded pipes.
2. Q: How to choose the material of seamless pipe?
A:General environment: choose Q235 or 20# carbon steel (low cost, easy to process);
Corrosive environment: choose 304/316L stainless steel or galvanized seamless pipe;
High temperature and high pressure: choose 15CrMo, 12Cr1MoV and other alloy pipes (specific temperature and pressure parameters must be provided).
3. Q: Can the size of seamless pipe be customized?
A:Regular specifications (outer diameter 6-630mm, wall thickness 0.5-50mm) can be customized in length (such as fixed length 6m, 9m);
Special caliber or wall thickness requires mold production, the minimum order quantity is higher (usually ≥5 tons), and the delivery time is extended by 2-4 weeks.
4. Q: How to detect the quality of seamless pipes?
Answer:Appearance: no cracks, folds, or scars on the surface, and uniform wall thickness;
Non-destructive testing: ultrasonic (UT) and eddy current (ET) detection of internal defects;
Pressure test: water pressure test (such as water pressure 10MPa, pressure maintenance for 5 minutes without leakage).
5. Q: How to prevent rust during transportation of seamless pipes?
Answer:Short-term transportation: can be naked in dry environment, and covered with waterproof cloth in humid environment;
Long-term storage: stored in a dry warehouse, ≥20cm from the ground, regularly check the surface rust, and re-oil if necessary.

If you need to purchase seamless pipes, it is recommended to clarify the following information in advance:

Use scenario: medium type (water/oil/gas), pressure, temperature;
Dimension accuracy: outer diameter/wall thickness tolerance requirements (such as precision machinery requires ±0.05mm);
Surface treatment: galvanizing, painting or other anti-corrosion requirements;
Certification requirements: such as API (petroleum industry) and ASME (American Society of Mechanical Engineers) certification