How many solenoid valves are needed to control the opening and closing of pneumatic piston regulating butterfly valve? The spraying process shall follow the following steps. The wear resistance of surface treatment sandblasting spraying (grinding) coating is a very important index. The wear resistance of wCCo/NiCrMo coating sprayed by spraying method is more than 2.5 times that of chromium plating. The corrosion test of WC, CoCr (JK120) coating sprayed by spraying method with small wear amount includes ASTM Bl17 salt spray test, GM9540P/B cyclic corrosion test and atmospheric corrosion test. 4340 steel surface was treated by chrome plating, WC Co spraying and Tribaloy400 spraying. After 500h salt spray test, wGCo coating had good corrosion resistance. It is reported that the salt spray corrosion resistance of sprayed WC Co, wGCo Cr, Cr203 and WC-17Co (JKl17) coatings is better than that of chromium plated coatings. WC CoCr (JK12O) coating has no corrosion after 750h salt spray corrosion. After 18 months of atmospheric corrosion test, the WC Co coating has almost no change.
④ Limit switch: it transmits the signal of valve switch position remotely. There are mechanical type, proximity type and inductive type.
