Introduction to the EN 10209 Standard
Date:2025-08-18
EN 10209:2013 is a key standard developed by the European Committee for Standardization (CEN). Its full title is "Weldable structural steel flat products for cold forming — Technical delivery conditions, coated with zinc and/or zinc alloys." This standard specifically addresses thin steel sheets used in building and engineering structures, which require excellent weldability and a corrosion-resistant protective coating (primarily hot-dip galvanized or zinc-iron alloy coating).
1. Core Objectives and Importance:
Ensuring Structural Reliability: This standard provides the material foundation for key load-bearing and non-load-bearing structural components, such as building frames, roofs, wall systems, and storage racks, ensuring their strength and durability.
Regulating Coating Quality: This standard specifies requirements for the thickness, uniformity, and adhesion of zinc or zinc alloy coatings, which are crucial for ensuring the long-term service life of steel in corrosive environments.
Ensuring Weldability: This standard specifies requirements for the chemical composition (especially carbon equivalent (CEV)) and mechanical properties of steel to ensure a smooth welding process, reliable weld quality, and the avoidance of defects such as cold cracking.
Promoting Consistency: This standard provides manufacturers, suppliers, designers, and contractors with unified technical specifications, streamlining material selection, procurement, and acceptance processes and ensuring consistent performance across different sources.
2. Key Content Covered by the Standard:
1) Scope of Application:
Cold-forming steel sheet, typically less than 3mm thick (some grades can reach 5mm).
Product forms primarily include wide flats, sheets, and strip (coil).
Suitable for hot-dip galvanizing (Z) or zinc-iron alloy (ZF) coating.
Primarily used in building structures (such as purlins, wall beams, roof support members, light steel keels), and other engineering structures requiring excellent formability, weldability, and corrosion resistance.
2) Steel Types and Grades:
The standard defines multiple steel grades, primarily differentiated by their minimum yield strength (ReH).
3) Coating Requirements (Core Corrosion Protection):
Coating Thickness (Minimum Local Value): The standard specifies the minimum single-point coating thickness requirements (in µm) for different steel grades and thickness ranges. Common requirements range from 20µm to over 85µm (for example, G115 indicates a minimum local thickness of 115g/m², approximately 16µm). A higher coating thickness means a longer expected service life.
Coating Surface: Options include regular spangle, small spangle, no spangle, or smooth finish.
Coating Adhesion: The coating must bond firmly to the substrate and withstand forming operations such as bending and cupping without peeling.
Surface Quality: Defects such as missing plating, bubbles, inclusions, and scratches must be clearly restricted.
4) Base Material Requirements (Core Mechanical and Welding Properties):
Chemical Composition: The content of elements such as carbon (C), manganese (Mn), phosphorus (P), and sulfur (S) is strictly controlled, with the carbon equivalent volume (CEV) being particularly limited to ensure excellent weldability. A lower CEV reduces susceptibility to cold cracking during welding.
