Product Parameters
Q235 Q345 ERW Welded Steel Tubes
Material and Specification
Material: Q235, Q345
Process: Electric Resistance Welding (ERW)
Standard: GB/T3091-2008, ASTM A53, BS1387, API 5L, API 5CT
Outer Diameter: 21.3mm-219mm
Thickness: 1.2mm-12mm
Length: 1-12m or customized
Surface Treatment: Oiled, black painted, galvanized
Key Features
The production process of electric resistance welded steel pipe is simple, the production efficiency is high, the varieties and specifications are wide and the cost is low, but the strength is generally lower than that of seamless steel pipe.
Chemical Composition
| Element | Q235 (%) | Q345 (%) |
| C (Carbon) | ≤0.22 | ≤0.20 |
| Mn (Manganese) | 0.30-0.70 | 1.00-1.60 |
| Si (Silicon) | ≤0.35 | ≤0.55 |
| P (Phosphorus) | ≤0.045 | ≤0.045 |
| S (Sulfur) | ≤0.045 | ≤0.045 |
Mechanical Properties
| Property | Q235 | Q345 |
| Yield Strength | ≥235 MPa | ≥345 MPa |
| Tensile Strength | 375-500 MPa | 470-630 MPa |
| Elongation | ≥26% | ≥21% |
| Hardness (HB) | ≤197 | ≤187 |
Physical Properties
| Property | Value |
| Density | 7.85 g/cm³ |
| Melting Point | 1420-1460°C |
| Thermal Conductivity | 51.9 W/mK |
| Specific Heat | 0.473 J/g°C |
| Electrical Resistivity | 0.15-0.18 x10^-6 Ω.m |
Process Performance
ERW welding ensures good dimensional accuracy and surface finish.
Suitable for various shaping operations such as round, square, rectangular, and special shapes.
Can be easily galvanized for corrosion resistance.
Steel Grade
Q235: Generally used for structural parts, such as bridges and buildings.
Q345: Suitable for structures with high loads, such as bridges, transmission towers, and vehicles.
Application
Construction: Structural support, building frames, scaffolding
Transportation: Pipeline systems, automotive parts
Machinery: Agricultural machinery, machine frames
Furniture: Metal furniture, storage racks
Other: Fencing, sign posts, greenhouse structures
Possible Alternative Grades
ASTM A500 Grade A, B, C
ASTM A513
BS EN 10219 S235JR, S275JR, S355JR, S235JRH, S275J0H, S355J0H, S355J2H
API 5L Grade B, X42, X46, X52, X56, X60, X65, X70, X80
This article provides an overview of Q235 Q345 ERW Welded Steel Tubes, including their material, specification, key features, chemical composition, mechanical properties, physical properties, process performance, steel grade, application, and possible alternative grades. These tubes are widely used in various industries due to their excellent properties and cost-effectiveness.
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