ASTM A283 Grade C Carbon Steel Plate Overview ASTM A283 Grade C is a low to intermediate tensile strength carbon steel plate widely used in structural and general construction applications. It belongs to the ASTM A283 specification, which covers four grades (A, B, C, and D) of carbon steel plates for moderate and lower strength requirements. Grade C offers a balanced combination of strength, formability, and weldability, making it suitable for fabrication into components such as tanks, bridges, buildings, and machinery parts. Chemical Composition The chemical composition of ASTM A283 Grade C ensures good weldability and machinability while maintaining structural integrity. Key elements include: - Carbon (C): 0.24% max – Provides strength but limits excessive hardness. - Manganese (Mn): 0.90% max – Enhances toughness and hardenability. - Phosphorus (P): 0.035% max – Minimized to avoid brittleness. - Sulfur (S): 0.040% max – Controlled to improve machinability and reduce cracking. Mechanical Properties ASTM A283 Grade C offers the following mechanical properties: - Tensile Strength: 380–485 MPa (55,000–70,000 psi) - Yield Strength: 205 MPa min (30,000 psi min) - Elongation: 22% min (in 200 mm gauge length) or 25% min (in 50 mm gauge length) These properties ensure adequate load-bearing capacity and ductility for structural applications. Applications Due to its moderate strength and cost-effectiveness, ASTM A283 Grade C is commonly used in: - Storage Tanks: For water, oil, and non-corrosive liquids. - Structural Frameworks: Beams, columns, and supports in construction. - General Fabrication: Machinery bases, agricultural equipment, and enclosures. - Shipbuilding: Non-critical marine components. Fabrication and Welding Grade C steel is easily weldable using common methods like shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and submerged arc welding (SAW). Preheating is generally unnecessary unless thick sections are involved. It can also be cut, drilled, and formed with standard tools. Surface Finish ASTM A283 Grade C plates are typically supplied as black steel, meaning they have a mill scale surface (a dark oxide layer formed during hot rolling). For corrosion-prone environments, additional coatings or paint may be applied. Advantages - Cost-Effective: Lower carbon content reduces production costs. - Versatile: Suitable for bending, welding, and machining. - Readily Available: Widely stocked in various thicknesses (3mm to 200mm). Limitations - Not suitable for high-stress or high-temperature applications. - Limited corrosion resistance; requires protection in harsh environments. Conclusion ASTM A283 Grade C carbon steel plate is a reliable, economical choice for structural and industrial applications where high strength is not critical. Its ease of fabrication and compliance with ASTM standards make it a preferred material for builders and fabricators worldwide. Proper selection based on project requirements ensures optimal performance and longevity.