Q235 steel coil is a common carbon structural steel material
1. Basic Properties
Material Standard: Q235 is a carbon structural steel specified in the Chinese GB/T 700 standard, corresponding to the international standard ASTM A36 (similar, but not identical).
Chemical Composition (Typical Values):
Carbon (C): ≤0.22%
Silicon (Si): ≤0.35%
Manganese (Mn): ≤1.4%
Phosphorus (P), Sulfur (S): ≤0.045% (impurities, affecting weldability and toughness).
2. Mechanical Properties
Yield Strength: ≥235 MPa (the "235" in "Q235" refers to yield strength).
Tensile Strength: 375-500 MPa.
Elongation: ≥26% (for thicknesses ≤16mm), with good plasticity and formability.
3. Coil Specifications
Thickness: Commonly 0.3mm to 6.0mm (cold-rolled coils are thinner, hot-rolled coils are thicker). Width: Typically 1000mm-2000mm, customizable.
Coil Weight: Typically 10-30 tons, depending on the manufacturer.
4. Surface Treatment
Hot-rolled steel coil: Surface scale is typically removed by pickling (e.g., SPHC coil).
Cold-rolled steel coil: Surface smooth, ready for subsequent processing such as galvanizing and color coating.
5. Applications
Construction: Steel structural frames, roofs, and walls (requires rust prevention).
Manufacturing: Automotive parts, mechanical components, and containers.
Home appliances: Housings and brackets (typically cold-rolled coil).
Pipes: Welded pipes and spiral pipes (primarily hot-rolled coil).
6. Processing Precautions
Welding: Easy to weld, but heat input must be controlled to avoid cold cracking.
Corrosion Protection: Galvanizing or painting is required for exposed environments (Q235 has average weather resistance).
Stamping: Cold-rolled coil is suitable for deep drawing, while hot-rolled coil requires annealing to improve ductility.
7. Market and Purchasing
Price Reference: Subject to fluctuations in the steel market, hot-rolled coil is approximately 4,000-5,000 yuan/ton (as of 2023).
Purchasing Key Points: Be sure to clarify thickness tolerance, surface quality (e.g., O5 finish), and implementation standards (e.g., GB/T 3274).
8. Comparison of Similar Grades
Q345: Offers higher strength but slightly higher cost, and is used for larger load-bearing areas.
SPCC: Cold-rolled sheet, prioritizes surface quality and is used for precision machining.