Characteristics of ASTM A515 Grade 65 Steel
1. Optimized Chemical Composition
Carbon (C): ≤0.28% (for thickness ≤25 mm), with the upper limit gradually increased for thicker plates (e.g., ≤0.33% for 100–200 mm thickness), balancing strength and toughness.
Manganese (Mn): 0.98–1.46%, enhancing hardenability and strength.
Phosphorus (P)/Sulfur (S): ≤0.035%, strictly controlling impurity content to reduce brittleness risks.
Silicon (Si): 0.13–0.45%, improving deoxidation effectiveness and corrosion resistance.
Alloying Element Design: Grain refinement achieved through microalloying (e.g., niobium, vanadium, titanium), enhancing strength and low-temperature toughness while maintaining high purity and low carbon equivalent to reduce welding crack susceptibility.
2. Superior Mechanical Properties
Tensile Strength: 450–585 MPa (65–85 ksi), suitable for high-pressure environments in medium- to high-temperature pressure vessels.
Yield Strength: ≥240 MPa (35 ksi), ensuring no plastic deformation under load.
Elongation: ≥19% (50 mm gauge length), demonstrating good plasticity for complex deformation requirements.
Impact Toughness: Maintains high toughness at low temperatures, preventing brittle fracture and making it suitable for engineering applications in extremely cold regions.
3. Adaptive Heat Treatment Processes
Normalizing Treatment: Required for plates >50 mm thick to refine grain structure and enhance overall performance.
Flexible Delivery Conditions: Plates ≤50 mm thick can be supplied as-rolled, normalized, or stress-relieved to meet varying operational requirements.
Simulated Post-Weld Heat Treatment (PWHT): Supports simulated PWHT for mechanical property test specimens to ensure stable welding joint performance.
4. Excellent Processing and Welding Performance
Machinability: Supports flame cutting, plasma cutting, CNC bending, and other processes, with minimal springback and high dimensional stability after forming.
Weldability: Compatible with manual arc welding, submerged arc welding, gas shielded welding, and other methods, ensuring welding joint strength matches the base material while meeting toughness standards and reducing welding defect risks.
Cutting Performance: Good machinability, rated at 70% (based on 1112 steel as 100%), suitable for mechanical processing.
5. Corrosion and High-Temperature Resistance
Corrosion Resistance: Enhanced through alloy element design and purity control, extending service life.
High-Temperature Resistance: Specifically designed for medium- to high-temperature pressure vessels, maintaining stable performance under elevated temperatures to prevent creep and relaxation.
