The valve spool hardness of hydraulic flow valves reached 65HRC, the German customer Fellix was impressed after receiving the first batch of shipments. Last week, he placed a reorder for 9,600 hydraulic flow valves, with a total value of more than 60,000 US dollars, and regarded as his preferred supplier for hydraulic valve purchasing In the hydraulic valve industry, more and more hydraulic valve manufacturers focus on homogeneous hydraulic valves, resulting in a decline in the level of hydraulic valve material selection and material reprocessing technology. Many hydraulic valve manufacturers think that their valve spool hardness meets the standard, but problems come out when they make samples or run production. The reason why most of hydraulic valve manufacturers can not solve the hardness problem well, mainly is: 1) without professional and systematic material knowledge, don't know how to choose the most suitable alloy steel material. 2) In the heat treatment of materials, most of them are led by the processing plants, mainly because the heat treatment is outward processing, and 20% of the outward processing is to change a place with one shot, and the hardness can not be guaranteed at all. Before the first cooperation with , Fellix consulted no less than 30 hydraulic valve manufacturers for the hydraulic flow valve with 65HRC valve spool hardness within 1 month. Only 2 said that 58HRC was the limit they can achieve. As for the other hydraulic valve manufacturers, no any feedback at all. Fellix was extremely disappointed. When browsing the Fellix accidentally encountered The article mentioned that 30 factories could not make the valve spool with a hardness of 65HRC, had already achieved in mass production, which made him curious about how the can be different. Fellix learned that has its own set of SOP for the selection of valve spool materials. Unlike the other hydraulic valve manufacturers, who use one material for nearly all hydraulic valves. will select the most suitable steel according to the working scene of hydraulic valve, the medium used and the hydraulic parameters of customers, combined with the wear resistance, linear expansion coefficient and deformation of different steel, such as Cr12MoV, 12CrNi3A 18crniwa, GCr15 and other high-grade tool steels. More importantly, has its own heat treatment plant, which can adopt different heat treatment methods in quenching, carburizing and nitriding according to different contents of steel. For example, pretreatment, quenching, cold treatment, tempering, aging, fine processing and other secondary aging, the aging temperature and holding time of these processes are the key.