Measures to prevent the brake disc from shrinking
With the popularity of vehicles, automobile brake discs are now becoming more and more popular with everyone. How much do you know about automobile brake discs?If you don't know, let's discuss with Xiaobian the introduction of measures to prevent the brake disc from shrinking.
Measures to prevent the brake disc from shrinking and loosening: the inner runner is evenly dispersed and the liquid iron is introduced to reduce local overheating of the disc and prevent the formation of artificial heat joints. According to the point of view of balanced solidification of cast iron parts, the thinner the thin-walled small pieces, the greater the shrinkage value, the more emphasis should be placed on filling the shrinkage.The shrinkage method can be filled by a pouring system, or the riser can be set to shrink.
When adopting the filling and shrinking scheme of the pouring system, the pressure head of the straight runner can be appropriately increased, such as increasing the height of the upper box, adding a gate ring, etc.; The horizontal runner is the main unit of skimmer and buoyancy, and when it is used for filling and shrinking, its cross-section size can be appropriately increased; the inner runner should be made into a short, thin, and wide shape. The inner runner is short (the horizontal runner is close to the casting), affected by the heat of the casting and the horizontal runner, as well as the effect of liquid iron filling and shrinking circulation, the inner runner will not solidify and close in advance, and it will remain unblocked for a long time. Thinness can prevent the introduction of the inner runner. A contact heat joint is formed at the place, which is wide to ensure a sufficient overcurrent area.
Once the casting enters the equilibrium solidification stage where graphitization expansion and contraction are offset, the liquid iron in the inner runner stops flowing, and it will solidify and intercept in time to improve the utilization rate of graphitization self-replenishment shrinkage. This is the adaptive adjustment effect of the short, thin and wide inner runner (riser neck) on the replenishment shrinkage.
For some castings with more severe shrinkage, a riser can be set to make up the shrinkage. The riser is preferably located at the beginning of the inner runner, or a riser can be set at the middle core to make up the shrinkage of the disc on the side of the inner runner.For thin-walled small pieces, secondary inoculation measures can be used, that is, inoculant is added to the small package for instantaneous inoculation, which improves the inoculation effect and promotes the growth of graphite nucleation. It is added to the bottom of the package and flushed into the liquid iron.