Thermal Shock Resistance of Cast Iron with Various Shapes of Graphite Precipitates
[ 1 ] Wydział Techniczny, Akademia im. Jakuba z Paradyża | [ P ] employee
2018
scientific article
english
- Graphite precipitates
- cast iron
- thermal shock
EN The influenceof a shape of graphite precipitates in cast iron on the thermal shock resistance of the alloy was initially determined. Investigations included the nodularcast ironand the vermicular one, as well as the cast iron containing flake graphite. The thermal shock resistance was examined at aspecial laboratory stand which allowed for multiple heating and cooling of specimens within the presumed temperature range. The specimens were inductively heated and then cooled in water of constant temperature of about 30°C.Therewere used flat specimens 70 mm long,5 mm thickin the middle part, and tapering like a wedgeover a distance of 15 mm towardsboth ends. The total length of cracks generated on the test surfaces of the wedge-shaped parts of specimens was measuredas a characteristic value inversely proportional tothe thermalshock resistanceof a material.The specimens heated up to 500°C were subjected to 2000 test cycles of alternate heating and cooling, while the specimens heated up to 600°C underwent 1000 such cycles. It was found that as the heating temperature rose within the 500-600°C range, the thermal shock resistance decreased for all examined types of cast iron. The research study proved that the nodular cast iron exhibited the best thermal shock resistance, the vermicular cast iron got somewhat lower results, while the lowest thermal shock resistance was exhibited by grey cast iron containing flake graphite.
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