Technological features of cast iron treatment

Анотація

The paper describes the use of vibration technology, which is an effective means of reducing residual stresses in castings. Vibration can be used to achieve a stress reduction sufficient to prevent further grooving of castings due to the redistribution of residual stresses. In addition, it was shown that residual stresses in cast iron castings can be reduced without vibration by additional static loading with holding under load. As a result of the work, the necessary data were obtained for assigning vibration modes. It was established that the amplitude of vibrations has a decisive influence on the magnitude of the reduction of residual stresses during vibration. The time required for the complete completion of the process of stress reduction under the action of vibration was determined. It was established that for cast iron castings, in which residual stresses reach approximately 10 kg/mm², the amplitude of vibrations during vibration should not exceed 3–4 kg/mm², otherwise there is a risk of cracks forming in the castings during vibration. After repeated vibration, the samples were observed for another four months. After this period, no changes in the magnitude of the stresses compared to the stresses remaining after vibration were detected. The results of this work provide grounds to recommend industrial testing of new methods of aging cast iron castings by vibration or static loading with the aim of their widespread introduction into industry.