SA 204 Grade B – Overview SA204 Grade B is a molybdenum-alloy steel plate specified under ASTM A204 / ASME SA204, mainly used in the manufacture of boilers and pressure vessels working at elevated temperatures. 🔹 Key Features: Standard: ASTM A204 / ASME SA204 Grade: B (middle grade between A and C) Alloy Type: Molybdenum steel Application: Pressure vessels, heat exchangers, boilers 🔹 Chemical Composition (Typical %): Element Grade B Carbon (C) 0.20 max Manganese (Mn) 0.44–0.94 Phosphorus (P) 0.035 max Sulfur (S) 0.035 max Molybdenum (Mo) 0.45–0.65 🔹 Mechanical Properties: Property Value Tensile Strength 485 – 620 MPa Yield Strength ≥ 275 MPa Elongation ≥ 22% (in 200 mm) 🔹 Equivalent Grades: Standard Equivalent Grade EN (Europe) 16Mo3 (widely used equivalent) DIN 1.5415 BS 621B or similar ⚠️ Note: 16Mo3 is often offered as an alternative due to wider availability, especially in European and Asian markets. 🔹 Applications: High-temperature pressure vessels Steam and hot oil boilers Heat exchanger shells Petrochemical reactors