FLORENTINA POTECASU, MARIAN BORDEI, ION SANDU STRUCTURAL ANALYSIS OF FRAGMENTS OF THE BROKEN COAT OF A CYLINDER WHICH LED TO THE DISMANTLING OF A COMBUSTION ENGINE The paper presents the structural analysis of cast iron fragments from the cylinder coat of a combustion engine, as a result of the broken down through explosion. Initially, determinations of the chemical composition were made and it was found that although the cast iron had the carbon content imposed. As a result, detailed microstructural analyzes were made regarding the shape, size and distribution of graphite in the cast iron as well as for the identification of structural constituents and constitutive phases. The same investigations were carried out on samples taken from a cylinder coat with a good functioning for comparison (blank samples). The metallographic study revealed characteristics of inappropriate graphite separations (graphite type B, D, E) and areas with specific structural constituents to the mottled cast iron that can cause breakage of the cylinder coat and excessive wear of the segments.
Keywords: microstructural analysis, combustion engine, chemical composition, metallographic study, mottled cast iron