The support size of a thin-walled steel casting is 400 mm × 310 mm × 270 mm, minimum wall thickness 4 mm, average wall thickness 5 mm, material zgd410-700. The product structure and casting process scheme are shown in Figure 1. According to this process scheme, more than 40% of the castings have insufficient pouring defects (Figure 1). The insufficient pouring defects are mainly concentrated in the parts “①” and “②” marked in Figure 1b, and there are also a few insufficient pouring defects in part “③”.
During casting pouring, the liquid metal is filled from bottom to top, in which the liquid metal flow distance of part “①” is the farthest. In addition, there is a square process hole on the left side of part “①”, which speeds up the cooling of liquid metal at the front of filling, resulting in the largest proportion of insufficient pouring defects of part “①”. In addition, in this gating system, the insufficient pouring part is finally filled, and there is no exhaust system, which may lead to “suffocation” and insufficient pouring. According to preliminary judgment, the main causes of insufficient pouring defects of castings are: low pouring temperature, slow pouring speed and “suffocation”.