What are the common types of structural steel materials?

1. Q235B (ASTM A36 / EN S235JR / JIS SS400)
   • The most universal and widely consumed structural steel grade in China, offering excellent cost-performance value.
   • Corresponding foreign equivalents: A36, SS400.
   • Applications: The vast majority of structural components, including steel beams, columns, purlins, braces, platforms, stairs, etc.
2. Q355B (Formerly Q345B) [Q355B (China GB) Equivalent to ASTM A572 Gr.50 / EN S355 / JIS SM490]
   • Low-alloy high-strength steel; offers higher strength compared to Q235.
   • Corresponding foreign equivalent: S355JR.
   • Applications: Large-span beams, crane beams, heavy-load columns, and critical load-bearing nodes.

• Q355C/D/E (Offers superior low-temperature toughness; commonly used in cold regions).
• Q420, Q460, Q690 (Higher strength grades; used for heavy-duty industrial plants and bridges).

Primarily used to produce C-sections, Z-sections, and U-sections.

• Q235B
• Q355B
• S350GD, S550GD (High-strength galvanized structural steel).

• DX51D+Z / DX52D+Z (Standard galvanized steel).
• S350GD+Z / S550GD+Z (High-strength galvanized steel for purlins). Commonly used for: Roof purlins, wall girts, and exposed structural components.

• Straight-seam welded pipes, seamless steel pipes: Q235B, Q355B.
• Commonly used for space frames / trusses: 20# steel, Q355B.

• USA: ASTM A36, A572 Grade 50
• Europe: EN S235JR, S355JR
• Japan: SS400, SM490
• Australia: G300, G350, G500