HYDROGEN CONTENT IN GREY IRON CASTINGS MADE BY THE LOST FOAM PROCESS

One of the main parameters that determine the correct run of pattern evaporation process is the type and volume of gas evolved from a foamed polystyrene pattern during its evaporation. The process of pattern evaporation takes place within a preset range of temperatures. The volume of the evolved gas depends on the temperature, and on the pattern volume and weight. One of the gaseous products of the foamed polystyrene pattern decomposition is hydrogen. Its content in the total volume of the evolved gas depends on the temperature at which the pattern evaporation takes place. Maximum hydrogen content in the total volume of gas may reach even 10%. In the present studies the effect of the products of the thermal decomposition of a foamed polystyrene pattern on the metal properties, especially on the content of hydrogen in this metal, was determined. The content of hydrogen was determined in grey iron samples obtained by the lost foam process. The tentative results of the investigations were plotted in the form of diagrams.

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