Shrinkage is a common defect of brake disc. The performance and safety of brake disc are greatly affected. So how do we prevent the brake disc from shrinking when we use it?

First of all, the molten iron can be introduced into the inner runner evenly to reduce overheating in the local parts of the plate and prevent the formation of artificial hot spots. According to the point of view of balanced solidification of cast iron, the thinner and smaller the piece, the greater the shrinkage value, and the more emphasis should be placed on filling and shrinkage. Filling shrinkage can be made by casting system or by setting riser.

In addition, when the feeding scheme of the gating system is adopted, the pressure head of the straight runner can be appropriately increased, such as increasing the height of the upper box and adding the gate ring; Runner is skimming and floating air of main unit, used for feeding, extensions can be appropriately increased its section dimension: the sprue should be made into the shape of a short, thin, wide, inside the sprue short (runner of distance casting), influenced by casting and hot runner, and effect of the flow of iron liquid filling fill shrink, sprue will not advance solidification and closed, open, time is long, thin, can prevent the SPR form thermal contact section, the width is to ensure that sufficient flow area.

In case of serious shrinkage of the brake disc, a riser can be set for filling shrinkage. The riser can be set at the beginning of the inner runner as far as possible, or a riser can be set at the middle core to fill and shrink the disc part on one side of the inner runner. For thin-walled small pieces, secondary inoculation measures can be adopted, that is, inoculant is added in the small bag for instantaneous inoculation to improve the inoculation effect and promote the growth of graphite nucleus, and then the inoculant is added at the bottom of the bag to inject iron liquid.