The article discusses the most important changes in the construction of permanent mould casting machines, as well as the method of casting engine pistons and their construction on the example of Federal-Mogul (FM) Gorzyce. The system of automatic cooling of the presently used permanent mould casting machines coupled with robots which pour the liquid alloy ensures uniform crystallization of the pistons and optimal efficiency of the casting process. As a result of the necessity to improve the engine efficiency and thus reduce the fuel consumption and harmful substance emission, the construction of the pistons has changed as well. The piston castings, which are produced by gravity casting for metal moulds, have undergone a diametric transformation. Typical piston designs for gasoline and Diesel engines are shown together with the most important parts of the piston, the crown (combustion chamber) and the guide part (skirt). Depending on the type of engine, the present pistons characterize in differently shaped crown, a slimmed internal construction as well as component participation (cooling channels and ring inserts), and the piston skirts undergo surface treatment procedures.

The article presents the most important causes of the unstable connection between cast iron ring inserts and the silumin casting of an engine piston. It is shown that manufacturing defects are mainly related to the alfin processing of inserts in Al-Si alloy (the so-called AS9 alloy). Exceeding the permissible iron content in AS9 alloy causes the crystallization of brittle -Al5FeSi phases. Their unfavorable morphology and large size are the main reasons for the weakening of the diffusion connection between the inserts and the piston, causing an unacceptable proportion of defective products. The study presented in this work was conducted under industrial conditions on a population of 10.000 pistons. Quality control data, production parameters, as well as the micro- and macro-structures of the cast iron inserts, and the interface area between the inserts and the silumin piston, were analyzed. Material and technological solutions have been proposed to reduce the occurrence of casting defects at the insert-piston joint. This includes the introduction of so-called "morphological correctors" of the -Al5FeSi phases, reducing the possibility of gaseous impurities in the AS9 alloy and optimizing the temperature of the alfin alloy.