SA 387 GR 5 CL 1 / CL 2 – Chromium-Molybdenum Alloy Steel Plate for High-Temperature Service SA 387 Grade 5 Class 1 and Class 2 are pressure vessel quality alloy steel plates designed for high-temperature service. These plates are alloyed with chromium (5%) and molybdenum (0.5%) to deliver excellent resistance to heat, oxidation, and corrosion, especially in environments involving elevated temperatures and pressures such as petrochemical, power generation, and refinery industries. The key difference between Class 1 and Class 2 lies in their tensile strength and temperature resistance, with Class 2 offering higher mechanical strength. Key Highlights: Excellent High-Temperature Performance: Designed to retain strength and structural integrity in environments exceeding 400°C (752°F). Enhanced Corrosion and Oxidation Resistance: Chromium and molybdenum improve resistance to hydrogen attack, sulfide corrosion, and oxidation in harsh atmospheres. Superior Weldability and Fabrication Properties: Suitable for welding and forming with standard techniques used in pressure vessel manufacturing. Two Classes for Versatility: Class 1: Lower tensile strength; suitable for moderate stress applications. Class 2: Higher tensile strength; ideal for more demanding conditions. Mechanical Properties Overview: Property SA 387 Gr 5 Cl 1 SA 387 Gr 5 Cl 2 Yield Strength ≥ 205 MPa ≥ 220 MPa Tensile Strength 415–585 MPa 515–690 MPa Elongation ≥ 20% ≥ 18% Temperature Resistance Up to ~600°C (dependent on conditions) Up to ~600°C Typical Applications: Petrochemical and Refining Equipment: Reactors, distillation columns, heat exchangers, and catalytic converters. Power Generation Systems: Boilers, steam drums, and pressure vessels operating under elevated temperatures. Oil & Gas Industry: Pressure-retaining parts in sour service and hydrogen-containing environments. Thermal Processing Plants: Components exposed to cyclical thermal loading and high stress. Conclusion: SA 387 GR 5 CL 1/2 plates offer dependable performance in high-pressure, high-temperature conditions. With excellent creep resistance, corrosion protection, and weldability, they’re a trusted choice for critical components in energy, oil & gas, and chemical processing industries.