The figure shows the hardness change of white cast iron in lost foam casting with and without vibration. It can be seen from the figure that the hardness of the vibration lost foam casting white cast iron is lower than that of the lost foam casting white cast iron without vibration.
According to the research results of nodular cast iron and grey cast iron, it can be speculated that the solidification undercooling of the alloy will increase when vibration is applied to white cast iron during lost foam casting, which will have the following effects on the primary austenite:
① The driving force during solidification of white cast iron is increased.
② The critical nucleation size of primary austenite is reduced, which is beneficial to the nucleation of primary austenite and increases the number of austenite grains in the melt.
③ The solidification range from liquidus to eutectic reaction temperature is increased, the austenite growth time is longer, and the content of primary austenite is increased.
The solidification structure of white cast iron consists of pearlite and ledeburite, which are the transformation products of primary austenite. In the vibration lost foam casting white cast iron, the content of primary austenite is lower than that of quotient, and the content of ledeburite is reduced. Therefore, the hardness of the vibration lost foam casting white cast iron is lower.