1.The difference in the implementation of standards
Q235B and Q355B are commonly used structural steel materials, mainly used in fields such as architecture, bridges, and ships. The differences between the two are as follows:
1. Different chemical compositions: Q235B has carbon (C) ≤ 0.22%, manganese (Mn) ≤ 1.4%, silicon (Si) ≤ 0.35%, phosphorus (P) ≤ 0.045%, and sulfur (S) ≤ 0.045%, while Q355B has carbon (C) ≤ 0.20%, manganese (Mn) ≤ 1.70%, silicon (Si) ≤ 0.50%, phosphorus (P) ≤ 0.030%, and sulfur (S) ≤ 0.030%.
2. Different strength: The yield strength of Q355B is 355MPa, which is about 100MPa higher than the yield strength of Q235B.
3. Different toughness: Q355B has better toughness than Q235B and can be used at low temperatures.
4. Different prices: Due to the more optimized composition, better strength and toughness of Q355B, the price is relatively higher compared to Q235B.
Steel grade Q235B equally the following grade :
China (GB) Q235B
Japan (JIS) SS400B
United States (ASTM): Gr.65
International (IOS) E235B
Europe (EN) S235JR
Steel grade Q355B equally the following grade :
China (GB) Q355B
Japan (JIS) SCM440B
United States (ASTM): Gr.50
International (IOS) E355B
Europe (EN) S355JR