Investment casting 3Cr13valve plate with cutting-free was conducted though using silica sol as the binder and middle-temperature wax pattern

which required the valve plate and the sealing surface without any defect and not to use the welding repair grinding method to repair the seal surface.In the trial production process

there exists the size deviation

beans

pitting surface.Through strictly controlling the investment process parameters and the workshop environment temperature

low temperature treatment for shell before dewaxing

controlling shell baking and pouring temperature

dimension of valve plate size met tolerance range.Beans were eliminated by breathing at the first stuccoing and prewetting at the second stuccoing.Through lighting wood to cover tin bucket to realize the casting solidification in reducing atmosphere

the pitting surface was eliminated.