3DR pressure reducing valve is a special type of pressure valve in hydraulic systems,which is widely used in various hot rolling production lines of steel rolling enterprises.Due to the lack of understanding of the valve by on-site inspection and maintenance personnel,it is difficult to start when the valve malfunctions.Therefore,the author has written this article based on years of practice.The article first provides a detailed introduction to the internal structure and working function of the pressure reducing valve.Secondly,based on this,it introduces the specific application of the pressure reducing valve in the hot rolling production line.Then,it analyzes the causes of its faults.Finally,it further discusses the handling methods and preventive measures that should be taken for its faults.I believe that this article will help improve the maintenance,fault diagnosis,and handling capabilities of maintenance personnel.