Performance difference of Q345A, Q345B, Q345C, Q345D, Q345E steel

Q345 is a kind of steel. It is a low-alloy steel (C<0.2%), widely used in construction, bridges, vehicles, ships, pressure vessels, etc. Q represents the yield strength of this material. The latter 345 refers to the yield value of this material, which is about 345MPa. Yield value decreases with increasing material thickness.

Q345 has good comprehensive mechanical properties, acceptable low temperature performance, good plasticity and weldability. Used as structures, mechanical parts, building structures and general metal structures that bear dynamic loads such as medium and low pressure containers, oil tanks, vehicles, cranes, mining machinery, power stations, bridges, etc. Can be used in hot rolled or normalized state. It can be used in various structures in cold regions below -40°C.

Classification

Q345 can be divided into Q345A, Q345B, Q345C, Q345D and Q345E. They represent different shock temperatures.

Q345A, no effect;

Q345B level, 20 ° normal temperature impact;

Q345C, 0 degree impact;

Q345D, - 20 degree impact;

Q345E -40 degree shock.

Under different shock temperatures, the shock value is also different.

chemical composition

Q345A: C≤0.20, Mn≤1.7, Si≤0.55, P≤0.045, S≤0.045, V0.02~0.15;

Q345B: C≤0.20, Mn≤1.7, Si≤0.55, P≤0.040, S≤0.040, V0.02~0.15;

Q345C: C≤0.20, Mn≤1.7, Si≤0.55, P≤0.035, S≤0.035, V0.02~0.15, Al≥0.015;

Q345D: C≤0.20, Mn≤1.7, Si≤0.55, P≤0.030, S≤0.030, V0.02~0.15, Al≥0.015;

Q345E: C≤0.20, Mn≤1.7, Si≤0.55, P≤0.025, S≤0.025, V0.02~0.15, Al≥0.015.

Q345 steel is a substitute for 12MnV, 14MnNb, 18Mb, 16MnRe, 16Mn and other old steel grades, not just a material of 16Mn steel. 16Mn is also different from Q345 in chemical composition.

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