What is the national standard for Q355 steel plate?
A: The core standard for rolled steel plates is GB/T 3274-2017 "Hot-rolled steel plates and strips of carbon structural steel and low-alloy structural steel". The technical requirements for grades refer to GB/T 1591-2018 "Low-alloy high-strength structural steel".
What do the letters/numbers in Q355 represent?
A: Q = the first letter of the pinyin for yield strength; 355 = the minimum yield strength of the steel plate, 355MPa; without a suffix, it is for ordinary carbon structural steel; with a suffix, it is a special grade (such as Q355B, Q355NHD).
What material type is Q355 steel plate?
A: It belongs to low-alloy high-strength structural steel, with a carbon content ≤0.20%, and the addition of alloying elements such as Mn and Si, balancing strength, plasticity, and weldability, distinguishing it from Q235 carbon structural steel.
What is the core difference between Q355 and Q235 steel plates?
A: The core difference is yield strength. Q355 ≥ 355 MPa, Q235 ≥ 235 MPa. Q355 has a higher alloy content, resulting in superior strength and weather resistance compared to Q235, but it is also more expensive.
What are some common grade suffixes for Q355 steel plates, and what do they represent?
A: Q355A/B/C/D/E: Quality grades, with increasing impact energy requirements. Grade E can be used at temperatures as low as -40℃.
Q355NH/ND: Weather-resistant, suitable for outdoor steel structures.
Q355GJ: For building structures, suitable for high-rise buildings and bridges.
Q355q: Bridge-specific steel.