Shrinkage is a common defect of brake disc. For brake disc safety parts, its performance and safety are greatly affected. So how can we prevent the brake disc from shrinkage when using?

First of all, the molten iron can be evenly distributed into the inner sprue to reduce the overheating of the local part of the disk and prevent the formation of artificial hot spots. According to the view of the balanced solidification of the iron castings, the thinner the small pieces, the larger the shrinkage value, and the more emphasis should be placed on feeding. Feeding mode can be feeding by pouring system or riser.

When the feeding scheme of the pouring system is adopted, the pressure head of the sprue can be increased properly, such as the height of the upper box and the gate ring; The cross sprue is the main unit of skimming and floating air. When it is used for shrinkage compensation, its section size can be increased appropriately. The internal sprue should be made into a short, thin and wide shape. The internal sprue is short (the cross sprue is close to the casting), which is affected by the heat of the casting and the cross sprue, and the effect of iron filling, shrinkage compensation and flow. The internal sprue will not be solidified and closed in advance, and will be kept unblocked for a long time. The thin sprue can be prevented from being closed in the The width of the contact hot spot formed at the entrance of the internal sprue is to ensure sufficient flow area.

In case of serious shrinkage of the brake disc, the riser can be set for feeding. The riser can be set at the beginning of the inner sprue as much as possible, or the riser can be set at the middle core to supplement the disc part on one side of the inner sprue. For the thin-walled parts, the second inoculation can be used, that is, adding inoculant in the small package for instantaneous inoculation, improving the inoculation effect, promoting the growth of graphite nucleation, adding at the bottom of the package, and flushing into the molten iron.