The most commonly used casting technique for the manufacture of aluminum parts in automobiles is the HPDC(High Pressure Diecasting) process. This process is a trend that automotive companies continue to increase the application of HPDC because cycle time of HPDC is much shorter than conventional casting methods such as gravity casting process and low pressure casting process. for this reason HPDC can lower manufacturing costs. However, HPDC has one fatal disadvantage. When there are complex flow paths and undercut shapes inside such as water pump housings and cylinder heads, this internal geometry cannot be implemented by HPDC, so the product is forced to be manufactured using low-pressure casting process or gravity casting process that are low in productivity but can implement internal geometry through the sand core. In general, low pressure casting process and gravity casting process are 30 to 50% more expensive to manufacture than HPDC. In order to overcome these shortcomings, this paper had researched "Salt Core Technology" that can be used in HPDC process. Salt core technology is considered to be the core technology that enables undercut shape to be applied to HPDC process, can replace gravity casting part which has undercut shape. Also, It can reduce the aluminum part weight up to 10% through reducing the wall thickness. Moreover, it can reduce the part cost around 10 to 15% through productivity improvement and using cheap aluminum alloy. Salt core shall have high strength to overcome 800bar in HPDC, but shall have low strength in decoring. In this study, we studied the recipes of salt core that can implement these characteristics. Through this study, Hyundai Motor Group has succeeded in mass production by applying Salt Core technology to aluminum parts and expects this technology to spread to other industries. The strength of the developed salt core is 15MPa or higher and is designed to withstand the high pressure of the high-pressure casting process. Using this research result, Hyundai Motor succeeded in mass production by applying Salt Core to aluminum parts.

Mr. JIYONG LEE, HYUNDAI MOTOR GROUP, REPUBLIC OF KOREA Mr. CHEOLUNG LEE, HYUNDAI MOTOR GROUP, REPUBLIC OF KOREA