Steel is classified into different grades based on its chemical composition and mechanical properties to meet the needs of various engineering applications. In China, ordinary carbon structural steel (carbon structural steel) is divided into several grades according to the national standard GB/T 700, among which Q195, Q235, and Q355 are three of the most commonly used grades.
Steel is classified into different grades based on its chemical composition and mechanical properties to meet the needs of various engineering applications. In China, ordinary carbon structural steel (carbon structural steel) is divided into several grades according to the national standard GB/T 700, among which Q195, Q235, and Q355 are three of the most commonly used grades. The main differences between the grades lie in their minimum yield strength, tensile strength, elongation, and application range.
1. Q195Yield Strength: ≥195 MPa
Tensile Strength: ≥345 MPa
Elongation: ≥26%
Characteristics: Low yield strength, suitable for general structural components with low strength requirements.
High elongation, possessing good plasticity and processing properties.
Applications: Mainly used in general steel structures such as light buildings and simple supports.
Also commonly used in the manufacture of utility poles, scaffolding, and guardrails.
2. Q235Yield Strength: ≥235 MPa
Tensile Strength: ≥375 MPa
Elongation: ≥24% (Grade A) or ≥22% (Grade B)
Features: Compared to Q195, Q235 has higher yield strength and tensile strength, making it suitable for a wider range of structural applications.
It has good weldability and cold formability, and is easy to process.
Applications: Widely used in construction, bridges, shipbuilding, and machinery manufacturing.
Suitable for manufacturing structural components such as beams, columns, frames, pipes, and containers.
3. Q355Yield Strength: ≥355 MPa
Tensile Strength: ≥470 MPa
Elongation: ≥20%
Features: Significantly higher yield strength and tensile strength, suitable for complex structures with high mechanical performance requirements.
Good toughness, excellent low-temperature impact resistance, and stable performance in harsh environments.
Applications: Primarily used in critical structures such as heavy construction, large bridges, high-rise buildings, high-pressure vessels, and mining machinery.
Suitable for applications subject to high stress and dynamic loads, such as crane booms and pressure pipelines.
Selection Recommendations:
Q195: Suitable for general structural components with low strength requirements, offering high cost-effectiveness.
Q235: Widely applicable to various structural components with medium strength requirements, offering good machinability.
Q355: Suitable for critical structural components with high strength and toughness requirements, ensuring safety and reliability during long-term use.
