Q: What is Q355 steel plate?
A: Q355 steel plate is a low-alloy high-strength structural steel plate in Chinese national standard (GB/T 1591-2018), replacing the former Q345 steel. Its yield strength is not less than 355MPa, widely used in construction, machinery and engineering structures.
Q: What is the difference between Q355 and Q235 steel plates?
A: The core difference is strength: Q355 yield strength (≥355MPa) is much higher than Q235 (≥235MPa). Q355 contains more alloy elements (Mn, Si, etc.), has better toughness and weldability, and is suitable for heavy-load structures; Q235 is carbon structural steel, used for general load-bearing parts.
Q: Does Q355 steel plate have different grades?
A: Yes. According to GB/T 1591-2018, Q355 is divided into Q355A, Q355B, Q355C, Q355D and Q355E grades, distinguished by impact test requirements and temperature adaptability.
Q: What is the corresponding international standard of Q355 steel plate?
A: It is equivalent to S355JR (EN 10025-2), ASTM A572 Grade 50 (partial performance matching), and JIS SS400 (high-strength grade alternative). Note that the chemical composition and mechanical property limits have slight differences, and customer confirmation is required for cross-standard use.
Q: What does the "Q" in Q355 stand for?
A: "Q" is the abbreviation of "Qu" (yield strength) in Chinese Pinyin, representing the yield strength index of the steel. The following number 355 is the minimum yield strength value in MPa.