Q345 steel is a kind of steel material. Q345 steel is carbon alloy steel Q345 steel has good comprehensive performance, good low temperature performance, good cold stamping performance, good welding performance and machinability.
Q345 steel is widely used in bridges, vehicles, ships, buildings, pressure vessels, etc. Q represents the yield of this material, and 345 refers to the yield value of this material, which is about 345MPa. And the yield value will decrease as the thickness of the material increases.
Q345 steel executive standard
The external implementation standard of Q345 is: gb709, and the internal implementation standard is: gb/t1591-94. Due to the implementation of the standard, this kind of steel plate is allowed to be delivered with negative tolerance. The latest implementation standard is GB/T1591-2018.
In addition, the latest standard of Q345, GB/T1591-2018, compared with the old standard, replaces Q345 steel grade with Q355 steel grade. The most obvious change is the change of Mn element content, which is adjusted from the original 1.0-1.60 to ≤1.60, and the minimum value is cancelled limit.
With the discovery of modern industry and the continuous advancement of science and technology, various trace elements are more widely used in steel plates, and the Mn content is no longer the only factor affecting the strength and mechanical properties of steel. Therefore, the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and the Standardization Administration of China jointly issued and implemented the low-alloy high-strength structural steel standard, canceling the limitation of the Mn content range and only specifying the maximum value.
