Effect of heat treatment on the surface quality and dimensional tolerance of hydraulic valve spool

Hydraulic valves have very important role in hydraulic industry. Spool is one of the main parts of these valves which defines the valve efficiency and application by determining the fluid flow. The dimensional tolerance and surface quality of spool are the main effective parameters concerning the valve application. Spool requires heat treatment after machining for achieving the desired level of hardness and getting ready for grinding. In this paper, the hydraulic valves spools have first been machined to reach to the desired dimensions. Then, heat treatment has been performed on them to obtain the appropriate hardness. Finally, the spool distortion induced by heat treatment and its surface quality after grinding has been measured has been measured and compared with each other.