Advantages of colour etching in quality control of graphitic cast irons

Abstract Graphitic cast irons are the most important and most widely used materials for the production of castings. Increasing requirements for the quality of these castings lead to increased demands on the control of foundry production from raw materials through technological operations to the finished product. An integral part of this control process is structural analysis, because the properties of graphitic cast irons depend mainly on their structure (on the shape, size and number of graphitic particles and on the character of a metal matrix in which graphite occurs). The paper deals with the structural analysis of graphitic cast irons using the classical black and white contrast, as well as the use of colour metallography, which enables to obtain additional information about the structure of cast iron. The article contains photographs of microstructures of graphitic cast irons, obtained using black and white etching, as well as colour etching. It deals with the advantages of colour etching compared to the use of classical black and white methods.