Effects of chill vent gap and sleeve-plunger tip clearance on the vacuum degree of mold cavity and mechanical properties in high vacuum diecasting.

To minimize the weight of automotive components, manufacturers have started to integrate large-scale Al automotive body parts. This large-area casting method is primarily based on large-scale die-casting. In particular, high-vacuum die-casting is being increasingly employed to obtain large-area castings with improved properties. However, this method requires intense heat treatment after casting and high vacuum in the mold cavity during the casting process. Moreover, the cavity vacuum of the mold is influenced by various variables such as the casting injection system, molds, and vacuum facilities. Therefore, optimal vacuum design considering these variables is crucial for achieving high quality and productivity in casting. In this study, we performed an analysis to determine how the chill vent gap and the sleeve-plunger clearance affects the vacuum degree of the mold cavity. The results show that the vacuum degree of the mold cavity and inner gas quantity decrease as the chill vent gap increases. Accordingly, tensile properties increase; at a vent gap of 1.50 mm, the tensile strength and elongation of the T6 treated specimens are the highest at 325.15 MPa and 2.26%, respectively. Conversely, the vacuum degree of the mold cavity and inner gas quantities increase with the clearance between the sleeve and plunger tip. Consequently, the tensile properties weaken. Moreover, beginning at a clearance of 0.25 mm, external air is drawn into the gap between the sleeve and plunger, thereby significantly increasing the amount of gas of N2 and O2. When the clearance between the sleeve and the plunger tip is 0.30 mm, the tensile strength and elongation of the T6 treated specimen are the lowest at 294.11 MPa and 1.20%, respectively. [ABSTRACT FROM AUTHOR]