Q: What is the role of manganese (Mn) in Q235 steel plate?
A: Manganese improves the strength and hardness of the steel plate and enhances its hot-rolling processing performance. The maximum manganese content in Q235 steel plate is 1.4%.
Q: What are the restrictions on silicon (Si) content in Q235 steel plate?
A: Silicon (Si) content should be ≤0.35%. Appropriate amounts of silicon can improve strength, but excessive amounts will affect the plasticity and toughness of the steel.
Q: What are the harmful effects of sulfur (S) on the performance of Q235 steel plate?
A: Sulfur causes hot brittleness in steel, making it prone to cracking during high-temperature processing. Therefore, high-quality grades of Q235 have stricter restrictions on sulfur content.
Q: What is the effect of phosphorus (P) on the performance of Q235 steel plate?
A: Phosphorus causes cold brittleness in steel and reduces low-temperature impact toughness. The restrictions on phosphorus content in Q235C/D are stricter than those in A/B.
Q: Is a deviation in the chemical composition of Q235 steel plate permissible?
A: Yes, a deviation is permissible, provided it complies with the requirements of GB/T 222-2006 "Permissible Deviations in Chemical Composition of Finished Steel Products".