What is the application difference between Q235B steel plate and Q345B steel plate

As alloy elements content in Q235B steel plate and Q345B steel plate is different, the applications of their Q235B steel plate and Q345B steel plate are also quite different.  

Q235B steel plate is carbon structural steel, which is made for metal construction that doesn’t have high demand for steel strength, such as tie rod, connecting rod, hook, coupler, bolt and nut, sleeve, shaft and welding parts.

While Q345B steel plate is low alloy structural steel, which is designed with good mechanical properties, low temperature performance, plasticity and good weldability. Q345B steel plate is always delivered in hot rolled or normalizing state. Q345B steel plate is most widely used in low pressure vessel, oil tank, vehicles, cranes, mining machinery, power stations, mechanical parts, building structure, general metal parts.