A novel process named local pressurization in the die casting was successfully used to deliminate shrinkage porosity at the thick section of the die castings recently. A movable local pressurization apparatus was fabricated and adopted to cast die castings on an industrial scale in the paper

which owns the following merits such as simple constructure

cheap and adjustable parameters. The effects of the pin style and the tolerance between and hole on the life span of pin were investigated. The optimized tolerance for the pin of d 8mm and 12mm diameter was attached and the life span of the pin was guaranteed. The influence of local pressurization parameters on the inner porosity at the castings was analyzed again. The results showed that bigger pressure from pin

less porosity. The pressurization effect is better when the local pressurization timing is earlier. The ratio of the castings without shrinkage porosity defect is more than 97% after local pressurization was adopted in the plant.