the material difference of Q345A, Q345B, Q345C, Q345D and Q345E

　　Q345 is a kind of steel material. It is a low alloy steel (C<0.2%), widely used in bridges, vehicles, ships, buildings, pressure vessels, etc.. Q represents the yield of this kind of material, the 345 refers to the yield value of this material, in the 345 or so. And the yield value decreases with the increase of the thickness of the material. Q345A, Q345B, Q345C, Q345D and Q345E is a class distinction, represented by the temperature, mainly temperature shocks are different, each class interval of 20 degrees Celsius, and Q345A level is no impact temperature request; Q345B is 20 degrees ambient temperature impact; Q345C is 0 degrees impact; Q345D grade is 20 degrees below zero; Q345E, is - 40 degrees of impact. At different impact temperatures, the impact values are also different. It is belong to a low alloy series in steel plate. In the low alloy material, this material is the most common. 16Mn is another name for Q345 in the past.