Research results concerning the application of ultrasound technique for determining the averaged thermal conductivity in walls of castings produced of cast iron(solidifying in a steady system)containing carbon precipi...Research results concerning the application of ultrasound technique for determining the averaged thermal conductivity in walls of castings produced of cast iron(solidifying in a steady system)containing carbon precipitates in a graphite form,are presented in the hereby paper.Investigations concern castings of unalloyed cast iron.The influence of the form of graphite precipitates on the cast iron thermal conductivity as well as on the propagation velocity of the ultrasound wave,including the longitudinal wave velocity CL,was investigated in the study.The influence of the graphite form,described by the shape indicator(f),on the thermal conductivity(l)(determined on samples by the steady heat flow method)as well as the influence of this indicator(f)on the wave propagation velocity(CL),was investigated.A series of melts of cast iron,of the near eutectic chemical composition,were performed.Magnesium introduced in a wide range,allowed obtaining various graphite forms from flake,via mixed,vermicular to nodular.Dependences:l=f(CL),CL=f(f)were determined and at the final phase the empirical dependencel=f(CL)was also determined.The thermal conductivity and ultrasound wave velocity were tested on the same samples.The thermal conductivity coefficient of cast iron(l)was changing in a wide range from approximately 32 to 46 W/s·m,while the wave velocity CL respectively:from approximately 4,300 to 5,800 m/s.The empirical dependencel=f(CL),determined in the described variability ranges,is of a linear character and the correlation level equals:R2=0.87.The validation of the experimental results was performed on cast iron castings of slag ladles,since they are required to be of a good thermal conductivity.The possibility of assessing the thermal conductivity directly in walls of such castings by means of non-destructive ultrasound method,was confirmed.The real thermal conductivity determined in the walls of the castings is used to simulate the heating and cooling process of slag ladles,ingot molds and similar structures,which was o展开更多
基金This research was performed within realization of Project:POIR.01.01.01-00-0965/17.
文摘Research results concerning the application of ultrasound technique for determining the averaged thermal conductivity in walls of castings produced of cast iron(solidifying in a steady system)containing carbon precipitates in a graphite form,are presented in the hereby paper.Investigations concern castings of unalloyed cast iron.The influence of the form of graphite precipitates on the cast iron thermal conductivity as well as on the propagation velocity of the ultrasound wave,including the longitudinal wave velocity CL,was investigated in the study.The influence of the graphite form,described by the shape indicator(f),on the thermal conductivity(l)(determined on samples by the steady heat flow method)as well as the influence of this indicator(f)on the wave propagation velocity(CL),was investigated.A series of melts of cast iron,of the near eutectic chemical composition,were performed.Magnesium introduced in a wide range,allowed obtaining various graphite forms from flake,via mixed,vermicular to nodular.Dependences:l=f(CL),CL=f(f)were determined and at the final phase the empirical dependencel=f(CL)was also determined.The thermal conductivity and ultrasound wave velocity were tested on the same samples.The thermal conductivity coefficient of cast iron(l)was changing in a wide range from approximately 32 to 46 W/s·m,while the wave velocity CL respectively:from approximately 4,300 to 5,800 m/s.The empirical dependencel=f(CL),determined in the described variability ranges,is of a linear character and the correlation level equals:R2=0.87.The validation of the experimental results was performed on cast iron castings of slag ladles,since they are required to be of a good thermal conductivity.The possibility of assessing the thermal conductivity directly in walls of such castings by means of non-destructive ultrasound method,was confirmed.The real thermal conductivity determined in the walls of the castings is used to simulate the heating and cooling process of slag ladles,ingot molds and similar structures,which was o
