The lost-foam casting of aluminum alloy components

Abstract

In the lost-foam casting process, liquid metal is poured directly onto a refractorycoated, foamed polymer pattern which is buried in loose sand. The polymer pattern undergoes thermal degradation and is gradually replaced by the molten metal, which solidifies and produces the casting. The inherent operating advantages of this innovative technique have generated considerable interest among casting manufacturers. Currently, the process is being utilized to manufacture a wide variety of ferrous and nonferrous components catering primarily to the automotive industry. Because the process is relatively new, there is a compelling need to quantify the influence of process parameters on microstructure and mechanical properties. Furthermore, the interaction of the thermal degradation products with the solidifying metal may produce several unique defects in the casting.

Wear Protective Effects of Tribolayer Formation for Copper Based Alloys in Sliding Contacts: Alloy Dependent Sliding Surfaces and Their Effects on Wear and Friction

“…In the present chapter two alternative production routes are evaluated for three copper based alloys. The near net shape technologies metal (powder) injection moulding (MIM) and lost foam casting (LF) are described in part 2, both are known for steel [3] and aluminium [4] but have not been commercialised for copper-based alloys and lack substantial basic knowledge in published literature. Yet, near net shape technologies are especially interesting for copper-based alloys due to the high raw metal costs.…”

Wetting and wicking of liquid polymer degradation byproducts into the pattern coating during lost foam casting of Al alloys

“…However, the occurrence of defects in the castings due to degradation products from the pattern is preventing its exploitation to its maximum potential. [1][2][3] During the mould filling stage, the foam patterns break down into viscous liquid and vapour degradation byproducts, which can become entrained or trapped in the liquid metal. 4 In addition, laps or folds can occur when two streams of molten metal meet and the oxides and pattern decomposition products (such as C rich films), covering the metal fronts prevent the two streams from fusing.…”

TMF criteria for Lost Foam Casting aluminum alloys

“…Recently due to process cost reduction goals, conventional Die Casting (DC) process is being replaced by Lost Foam Casting (LFC) process 15, 16 . LFC uses almost a quarter less energy and a third less molten metal than conventional casting 17 . The advantages of LFC over DC process are then: the low cost of foam, unbounded sand, possibility of complex shapes with internal channels, elimination of cores and parting lines and reduced grinding and finishing costs 18…”