Surface hardening of Q345NH weathering steel plate

Quenching of Q345NH weathering steel plate is a kind of heat treatment to improve the overall hardness. However, there are many Q345NH weathering steel plate used to make mechanical parts that only require hard appearance but soft inside. Q345NH weathering steel plate has this effect for the purpose of the operation method, called surface hardening.

The surface hardening of Q345NH weathering steel plate is as follows:

(1) High frequency quenching: put Q345NH weathering steel plate into high frequency coil and turn on high frequency current. At this time, induced current will be generated in the workpiece. The high frequency current is only concentrated on the surface of Q345NH weathering steel plate, so as long as the surface of Q345NH weathering steel plate is heated. This method of heating and quenching is called high frequency induction hardening.

(2) Flame quenching: This is the use of oxygen and other gas flame stop heating quenching method.

(3) Carburizing and quenching: in order to increase the surface carbon content of Q345NH weathering steel plate, put Q345NH weathering steel plate into carburizing agent to stop heating carburizing and quenching. Liquid carburizing agents such as solid carburizing agents such as charcoal and coke and gas carburizing agents such as CO are used as carburizing agents. When heating is stopped in the carburizing agent, the carbon element penetrates into the surface of Q345NH weathering steel plate, which only makes the surface of Q345NH weathering steel plate become high carbon Q345NH weathering steel plate. The carburizing and quenching layer can reach the depth in millimeter.