Reducing pouring “temperature” to reduce sand hole and air hole defects of large steel castings
Reducing the pouring “temperature” is another important measure to reduce the defects of sand holes and pores in castings.
Due to the volume expansion of quartz sand when heated, the surface of medium-sized cavity is heated and expanded after being radiated by molten steel during pouring. The surface layer is separated from the inner layer and falls into liquid steel, resulting in sand holes and pores. In order to reduce the heat radiation time, every effort should be made to improve the pouring speed. In addition to “time”, there are also “temperature” and “distance” affecting the “radiation heat transfer intensity”. “Distance” is beyond our control; The “temperature” can be properly controlled.
Reducing the pouring “temperature” can prevent sand sticking of castings and improve the surface quality of castings.
Reducing the pouring “temperature” can alleviate the feeding pressure of the riser and improve the compactness of the internal structure of the casting.
Reducing the pouring “temperature” can reduce the oxidation film on the molten steel surface during pouring, so as to reduce the inclusions in the casting.
Lowering the pouring “temperature” can prevent the occurrence of “hot cracks”.