Description of S235JR (E235D) Square Steel Pipe S235JR (also designated as E235D) is a non-alloy structural steel grade widely used in construction and engineering applications. This material is known for its excellent mechanical properties, weldability, and formability, making it a preferred choice for manufacturing square steel pipes. Material Properties S235JR (E235D) is a low-carbon steel with a minimum yield strength of 235 MPa and good ductility. The chemical composition typically includes: - Carbon (C): ≤ 0.17% - Manganese (Mn): ≤ 1.40% - Phosphorus (P): ≤ 0.035% - Sulfur (S): ≤ 0.035% The "JR" designation indicates that the steel has been impact-tested at room temperature (20°C), ensuring sufficient toughness for structural applications. The "D" in E235D signifies improved impact resistance at lower temperatures (-20°C), making it suitable for environments with moderate cold conditions. Square Steel Pipe Characteristics Square steel pipes made from S235JR (E235D) offer several advantages: 1. High Strength & Durability – The material provides excellent load-bearing capacity, making it ideal for structural frameworks, supports, and machinery components. 2. Weldability & Machinability – Due to its low carbon content, S235JR can be easily welded and machined without significant risk of cracking or brittleness. 3. Corrosion Resistance – While not inherently corrosion-resistant like stainless steel, S235JR pipes can be galvanized or painted for enhanced protection in harsh environments. 4. Dimensional Accuracy – Square steel pipes are manufactured with precise tolerances, ensuring uniformity in construction and industrial applications. Applications S235JR (E235D) square steel pipes are commonly used in: - Construction – Building frames, roofing, and scaffolding. - Infrastructure – Bridges, railings, and support columns. - Industrial Machinery – Conveyor systems, storage racks, and equipment frames. - Automotive & Transportation – Chassis components and structural reinforcements. Standards & Compliance This steel grade complies with European standards (EN 10025-2 for S235JR and EN 10210 for structural hollow sections). It is also equivalent to ASTM A36 in terms of mechanical properties but differs slightly in chemical composition. Conclusion S235JR (E235D) square steel pipes are a versatile and cost-effective solution for structural and mechanical applications. Their combination of strength, weldability, and dimensional stability makes them suitable for a wide range of industries. Proper surface treatment (e.g., galvanizing or painting) can further extend their service life in corrosive environments. For specific project requirements, consulting technical data sheets and relevant standards is recommended to ensure optimal performance.