Fabrication of lotus type through-holes using the semisolid condition

Abstract

In this paper, an easy casting method of an ingot with through holes is presented. The Core-Bar-Pulling Method is proposed to improve the disadvantages of the lotus type porous metal. The through holes were formed by pulling core-bars from a semisolid ingot. Holes with diameters ranging from 0.5 to 5 mm and length 50 mm were made in Al–Si alloy ingots. The relationship between temperature and formability of the holes was investigated by using hypo-eutectic Al–Si alloys. The pulling of core-bars and the forming of holes were easy, under the condition that the Si content was less than 6 mass%. This means that the forming of holes in Al–Si alloys is easy under the condition that flow ability at semisolid condition decreases. The core-bar could be pulled at solid condition at the Si content less than 1%. The deformation of the hole was investigated by comparing the hole-size with the core-bar size. There was no tendency among the core-bar pulling-temperature, Si content and hole-deformation. The shape of the hole fabricated at the solid condition was better than that fabricated at the semisolid condition.