1、 Core characteristics and advantages of seamless steel

Material Definition and Standards

Seamless steel pipe is a seamless steel pipe made by hot rolling, cold drawing or cold rolling processes, with uniform mechanical properties and dense structure. The implementation standards include:

National standards: GB/T 8162-2018 (for structural use), GB/T 8163-2018 (for fluid transport)

American standards: ASTM A53/A106 (carbon steel), ASTM A312 (stainless steel)

European standards: EN 10210 (hot rolling), EN 10216 (for high temperature and high pressure)

Core performance parameters

Summary of Core Advantages

Zero weld defects: no weakening of the heat affected zone, 50% extension of fatigue life (ASTM E466 standard);

High strength and lightweight: reduce wall thickness by 15% under the same pressure, saving material costs;

Extreme environment adaptation: Stable operation at -196 ℃~550 ℃ (using low-temperature steel such as 09MnD).

2、 Product series and technical parameters

General structural pipe

Material: 20 #, 45 # Q345B

Specifications:

Outer diameter: Φ10-Φ630mm

Wall thickness: 1.5-50mm

Length: 6-12m (cutting accuracy ± 5mm)

Application: Building trusses, mechanical spindles, hydraulic supports

High pressure fluid delivery pipe

Material: 20G, 15CrMo, P91 (high-temperature alloy)

Voltage resistance level:

Room temperature: ≤ 50MPa (1.5 times the hydrostatic test pressure)

High temperature: Endurance strength ≥ 100MPa at 550 ℃ (ASME B31.3 standard)

Application: Petroleum cracking furnace tubes, power plant boiler pipelines

Precision hydraulic/pneumatic tubing

texture of material: ST52、 304/316 stainless steel

Process: Cold drawing+precision honing, inner wall roughness Ra ≤ 0.4 μ m

Tolerance:

Outer diameter ± 0.05mm (Φ 6- Φ 50mm)

Straightness ≤ 0.3mm/m

Special purpose pipe

Low temperature seamless pipe:

Material: 09MnNiDR, X12CrNi9 (-196 ℃ impact energy ≥ 80J)

Application: LNG storage tanks, liquid nitrogen transportation

Corrosion resistant alloy pipe:

texture of material: Inconel 625、Hastelloy C276

Corrosion resistance: resistant to 98% sulfuric acid and seawater with a total corrosion rate of ≤ 0.02mm/year

3、 Manufacturing process and core technology

hot-rolling process

Perforation: Heat the round billet to 1200 ℃ and roll it diagonally to form a hollow capillary tube;

Pipe rolling: The continuous rolling mill reduces the wall diameter and the final rolling temperature is ≥ 850 ℃;

Finishing: straightening+eddy current testing (EN 10246-3 standard).

Cold drawing/cold rolling process

Diameter reduction rate: 20% -50% (deformation amount of each pass ≤ 30% to prevent cracking);

Lubrication: Phosphating and saponification treatment, friction coefficient ≤ 0.08;

Annealing: Protective atmosphere annealing (hydrogen/nitrogen), hardness fluctuation ≤ 10HB.

Surface treatment technology

Galvanization: hot-dip galvanized layer ≥ 610g/m ² (GB/T 3091);

Sandblasting: Sa2.5 cleanliness level (ISO 8501-1);

Inner wall coating: epoxy resin coating thickness of 150-300 μ m (API RP 5L2).

Contact

Mobile number: 13848510731

Landline number: 0471-6490861

Address: Inside the courtyard of the Outer Transport Company, diagonally opposite the government of Haoqinying Town, Xincheng District, Hohhot City, Inner Mongolia (National Highway 110)