Selection of parting surface and pouring position of nodular iron main reducer shell cover to avoid shrinkage defects

For the horizontal box free molding line, the parting surface of the production main reducer shell cover is generally selected in the middle of the flange. The selection of the parting surface is not only conducive to the mold lifting, but also convenient for the adjustment of the casting dimensional error caused by the mold lifting and other reasons.

For the main reducer shell cover produced by the horizontal line, there are generally two choices of pouring position, i.e. the disc face up or the disc face down, as shown in (a) and (b) in the figure. If the disk surface is upward, the product is mainly located in the lower box, which is generally a top injection gating system. The advantage is that the pressure head is high, the hot spot is conducive to gravity self feeding, and the shrinkage cavity and porosity tendency of the casting is small; The disadvantage is that the casting is easy to form sand washing defects. The other is the disk face down, generally the bottom injection gating system, with stable mold filling and good casting surface quality. The disadvantage is that the upper box of the product is high and the shrinkage and porosity tendency of the hot spot is large.

Through trial production and verification, the pouring position with the disk face down is finally selected, and the casting process is designed to ensure that the appearance quality meets the technical requirements.