Q235B steel pipe is manufactured from high-quality strip steel coils and is widely used for mechanical tubing, liquid transport, structural frameworks, and general engineering applications.
Known for its good bearing capacity, plasticity, weldability, and moderate strength, Q235B steel pipes are a cost-effective and versatile choice for various industries.
Production Process
The production of Q235B steel pipes involves precise engineering and strict quality control:
Raw Materials: High-grade strip steel coils, welding wire, and flux.
Preparation: Strip leveling, edge trimming, surface cleaning, and pre-bending.
Forming: Roll forming via internal or external control to achieve precise pipe diameter and alignment.
Welding: Automatic double-wire or single-wire submerged arc welding (SAW) ensures strong, stable welds. Both internal and external welds are performed using Lincoln electric welding machines.
Inspection:
Online ultrasonic flaw detection ensures 100% weld coverage.
Manual ultrasonic and X-ray inspections for weld intersections.
Hydrostatic pressure testing with controlled parameters.
Cutting & Finishing: Pipes are cut to size with air plasma machines and the ends are machined for precise bevel angle and verticality.
This process ensures the production of high-quality, reliable steel pipes suitable for various demanding applications.
Specifications
| Pipe Type | OD Range | Wall Thickness (WT) |
|---|---|---|
| SSAW | 219–3120 mm | 3–25 mm |
| LSAW | 16″–64″ | Max 50 mm |
| ERW | 1/8″–24″ | Max 26.5 mm |
| SMLS | 1/8″–36″ | 1.25–50 mm |
Other Details:
Standards: ANSI, ASME, ASTM, API, SAE, BS, AGA, AWWA, ISO, DIN
Pipe Schedules: SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS
Shapes: Round, Half Round, Square, Rectangular, Custom
Length: 3 m to 18 m (customizable)
Ends: Beveled, Plain, Threaded
Surface Coatings: Epoxy, Coal Tar Epoxy, 3PE, Varnish, Bitumen, Black Oil (customizable)
Certificates: EN 10204/3.1B
Chemical Composition
| Grade | C (%) | Mn (%) | Si (%) | S (%) | P (%) |
|---|---|---|---|---|---|
| Q195 | 0.06–0.12 | 0.25–0.50 | ≤0.30 | ≤0.045 | ≤0.05 |
| Q215 | 0.09–0.15 | 0.25–0.55 | ≤0.30 | ≤0.05 | ≤0.045 |
| Q235 | 0.12–0.20 | 0.30–0.67 | ≤0.30 | ≤0.045 | ≤0.04 |
| Q345 | ≤0.20 | 1.00–1.60 | ≤0.55 | ≤0.04 | ≤0.04 |
Mechanical Properties
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) |
|---|---|---|
| Q195 | 195 | 315–430 |
| Q215 | 215 | 335–450 |
| Q235 | 235 | 370–500 |
| Q275 | 275 | 410–540 |
Key Features:
Straight seam pipes: simple process, high efficiency, lower cost.
Spiral welded pipes: higher strength, suitable for large diameters.
Standards Classification
| Type | Standard | Application |
|---|---|---|
| Spiral Submerged Arc Welded (SY5036-83) | Pressure-bearing fluid transport | Oil and natural gas pipelines |
| Spiral High-Frequency Welded (SY5038-83) | Pressure-bearing fluid transport | Oil, gas, and water pipelines |
| Spiral Submerged Arc Welded for Low Pressure (SY5037-83) | Low-pressure fluids | Water, air, steam |
| National Standard | GB/T9711.1-1997 | Oil & gas pipelines, Grade A/B |
| API | API-5L (PSL1 / PSL2) | Petroleum pipeline transportation |
Applications
Q235B steel pipes are widely used for:
Mechanical tubing and structural frameworks
Liquid, gas, and oil transportation
Construction and engineering projects
Pile pipes for foundations
General mechanical parts with low to moderate strength requirements
Testing & Quality Assurance
Each Q235B pipe undergoes rigorous testing:
Chemical composition analysis
Mechanical testing: tensile strength, yield strength, elongation
Technical tests: flattening, blow, impact, flaring, bending, hardness
Dimensional inspection
Nondestructive tests: ultrasonic, eddy current
Hydrostatic pressure tests
This ensures full compliance with international standards and guarantees pipe performance and reliability.
