Microstructural Analysis of the Failure of a Cast Iron Cylinder Head of a Thermoelectrical Plant Motor
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Large motors, such as those that propel ships or generate energy for thermoelectrical plants, for instance, use cylinder heads produced with nodular cast iron. Such components are manufactured by a casting process which must be strictly controlled to prevent the appearance of defects that may spoil the performance of the component in service. When these defects arise, they usually lead to the failure of the cylinder head, mainly causing fluids leakage that can harm or even impede the motor performance. In this study, the microstructure of the material was characterized, with the purpose of investigating the possible causes of the failure, through the use of techniques such as optical microscopy and scanning electron microscopy. Brinell hardness tests were also performed. The results revealed that inadequate casting procedures probably caused the defects and subsequent failure of the cylinder head.
KeywordsCasting iron Failure analysis Microscopy
The authors would like to thank Rafael de Abreu Vinhosa for sample preparation, Ricardo Silva Tavares Mello for helpful information about motor mechanics, and CENANO/INT for SEM images. CNPq (Brazilian Council for Scientific and Technological Development) and FAPERJ (Research Funding Agency of Rio de Janeiro) must be acknowledged for financial support.
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