Kostyk V. Elaboration of Methods of Metal Descaling by Thermal Shock

3. Subject of investigation is cylindrical rolled product with industrial scale. The aim of this work is the elaboration of new ecologically pure and economically effective methods of metal descaling by rapid high frequency heating and following cooling which ensure high level of scale removing without quenching of metal surface. Methods of investigation: electron microscopy, X-ray diffraction, metallographic analysis, hardness and microhardness determination, scale mechanical characteristics measuring. Mathematical dependences are received which allow to calculate temperature fields and stresses appearing in scale during rapid heating to different temperatures. Mechanism of scale sepa- ration is investigated. Theoretical analysis of stress changing dependent on temperature is fulfilled. Conditions of heating by high frequency current are formulated. New methods of scale removing which ensure high level of descaling (higher than 80 %) are elabo- rated. Structural changes in surface layer of steel emerg ing during high frequency heating are investigated. Technological process is adopted by "Starokramatorsky Machinebuilding Plant" Ltd. Labora- tory and industrial equipment are designed Plans and specifications of industrial equipment are given to Orlovsky steel-rolling plant. Area of application is metallurgical, metalware and machine building plants.