The blackening of valve block is also called bluing, which is a surface treatment process that the workpiece forms a layer of blue or black oxide film on the surface of the workpiece at room temperature or heated to an appropriate temperature in air, steam or chemical solution to improve its corrosion resistance and appearance.

Hydraulic valve block (referred to as hydraulic valve) is the control element in the hydraulic system, which is used to control the pressure, flow and flow direction of the fluid in the hydraulic system, so as to meet the requirements of different actions of various executive elements.

Hydraulic valve block is a kind of automatic component operated by pressure oil. It is controlled by pressure oil of distributing valve. It is usually combined with electromagnetic distributing valve. It can be used for remote control of oil, gas and water pipeline system of hydropower station.

Design and processing of valve block the initial thickness of the valve block is set as 5 times of the large diameter, and then gradually reduces according to the specific design; When designing the passage, we should arrange the passage reasonably.

In general, the total number of hydraulic components contained in the hydraulic valve block will not exceed 10, so the number of hydraulic components allocated to each surface will not exceed 10, generally about 3 to 5.