IMPACT OF COOLING CHARACTER ON STRUCTURE AND CTE OF INVARALLOY WITH 0,6% C

Abstract

The qualitative and quantitative analysis of distribution of structural components (-phase + graphite) in the carbon-containing invar alloy with 0,6% C was conducted. It is demonstrated that velocity of crystallization produces a strong influence on the dispersion of graphite and on the volume fraction of graphite components in the alloy, i.e. at faster cooling the graphite volume fraction and its dispersion are noticeably higher than at slower cooling. The linear thermal expansion coefficient of both slowly cooled and fast cooled alloys maintains its values constant at heating temperatures lower 200 oC. However, in the alloy received as a result of fast cooling this coefficient values are lower than at slow cooling which can be explained by a lower content of carbon in the -phase, being a carrier of invar properties, of the slowly cooled alloy.