Q355D is a low-alloy, high-strength structural steel designed for load-bearing applications in machinery, construction, and steel structure fabrication.
The “Q” denotes yield strength (“Qu”), and “355” indicates a minimum yield strength of 355 MPa. The “D” classification refers to impact toughness at low temperatures (–20°C), making it suitable for cold-region construction and outdoor industrial environments.
With its combination of strength, weldability, and impact resistance, Q355D provides consistent performance in bridges, pressure vessels, offshore structures, cranes, and high-rise steel frames.
Chemical Composition (% by weight)
C: ≤ 0.20
Si: ≤ 0.55
Mn: ≤ 1.70
P: ≤ 0.030
S: ≤ 0.030
Nb, V, Ti: trace microalloying elements for grain refinement and strength enhancement
Mechanical Properties and Key Advantages
Minimum yield strength: 355 MPa (for ≤16 mm thickness)
Excellent weldability and formability for complex structural fabrication
Reliable low-temperature impact resistance (Charpy V-notch ≥27J at –20°C)
Good fatigue strength and dimensional stability under stress
Suitable for welding, cutting, and forming without performance degradation
Q355D’s balanced composition ensures structural integrity in both static and dynamic load conditions. Its uniform microstructure and controlled impurities make it a versatile material for long-span and high-load projects.
Typical Applications
Q355D is widely used in industries where high strength and reliable toughness are required:
Steel structures and frames for industrial and civil buildings
Bridge beams, crane arms, and lifting equipment
Heavy machinery and mining components
Pressure vessels and energy equipment
Offshore platforms, shipbuilding, and marine structures
Equivalent Grades:
EN: S355J2
ASTM: A572 Grade 50
JIS: SM490YB
Quality Assurance from ChinaSpecSteel
ChinaSpecSteel provides Q355D structural steel in cooperation with Jiyuan Iron & Steel Group, one of China’s top producers of special and structural steels.
Jiyuan’s long-process integrated production system — from ironmaking to steelmaking, rolling, and testing — guarantees stable composition, fine grain control, and consistent performance.
Available Supply Forms:
Hot-rolled plates, coils, and sections
Normalized or TMCP-rolled material upon request
Customized thickness, width, and length for project-specific requirements
Mill test certificates (EN 10204/3.1) and optional third-party inspection (SGS/BV)
Export-standard bundling, palletizing, and seaworthy packaging
Processing Support:
Flame or plasma cutting
Surface shot-blasting and anti-rust coating
Precision machining for OEM fabricators
Production Capability — Jiyuan Iron & Steel
Jiyuan Iron & Steel Group is equipped with modern metallurgical and refining technology, achieving international-level steelmaking quality.
The company serves as a major production base for special and high-strength steels, offering comprehensive steel types such as bearing steel, spring steel, gear steel, cold heading steel, alloy structural steel, carbon structural steel, free-cutting steel, high-strength wear-resistant steel, tube billet steel, anchor chain steel, and continuous cast iron profiles.
Further-processed materials include precision wire, heat-treated bars, bright bars, and fasteners, serving global industries such as construction, energy, automotive, shipbuilding, and machinery manufacturing.
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