What is the composition of ASTM A204 Grade B steel plate?

ASTM A204 Grade B is a molybdenum-alloyed steel plate primarily used for welded boilers and pressure vessels operating at elevated temperatures. Here is the detailed composition of ASTM A204 Grade B:

1. Carbon (C): The maximum carbon content for ASTM A204 Grade B is 0.20%.

2. Manganese (Mn): The maximum manganese content is 0.90%.

3. Phosphorus (P): The maximum phosphorus content is 0.025%.

4. Sulfur (S): The maximum sulfur content is 0.025%.

5. Silicon (Si): The maximum silicon content is 0.15-0.40%.

6. Chromium (Cr): The maximum chromium content is 0.85-1.00%.

7. Molybdenum (Mo): The molybdenum content for ASTM A204 Grade B is specified to be 0.45-0.60%. Molybdenum enhances the material's mechanical properties and provides improved corrosion resistance, particularly in high-temperature applications.

8. Iron (Fe): Balance - Iron is the primary element that makes up the remainder of the composition after considering the above elements.

These alloying elements play a crucial role in defining the mechanical properties and performance characteristics of ASTM A204 Grade B steel, making it suitable for high-temperature service in pressure vessel applications. The controlled composition ensures the material meets specified requirements for strength, toughness, and weldability necessary for its intended use in demanding industrial environments.