ISO 4131:1979

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ISO 4131:1979 outlines the method for determining the free-swelling index of hard coals, an important property for evaluating their suitability for coke production in industrial applications like steelmaking.

ISO 4131:1979 is an international standard that specifies a method for determining the free-swelling index (FSI) of hard coals. The free-swelling index is a measure of the expansion of a coal sample when it is heated under controlled conditions. This index is particularly important in the context of coking coal used in metallurgical processes, especially in the production of coke for blast furnaces.