A statistical study on the relationship between tensile strength and ultrasonic velocity of cast iron

One of the most recent goals of metallurgists is to predict mechanical properties of cast iron through computer simulation. Recent research has shown that the mechanical property map of gray and ductile iron castings can be obtained from computer modeling. However, the validation of the computation results was very expensive and difficult because the tensile strength of the casting only can be obtained from sectioning the casting. A statistical study on the relationship between tensile strength and ultrasonic velocity has been conducted. Some findings are reported in this paper. Experimental results have proved that linear relationships with statistically significance existed between tensile strengths and ultrasonic velocities for gray and ductile irons. Ultrasonic velocity readings increased with the increase of tensile strength of cast iron. Two regression equations have been obtained for gray iron and ductile iron, separately. Since thickness of at different location of the casting can be measured by CMM easily, through measuring the ultrasonic velocity, the local tensile strength of the casting can be evaluated. It is expected that ultrasonic velocity measurements will provide a powerful tool in tensile strength prediction in casting quality control and computer simulation of mechanical properties. (C) 2003 Maney Publishing.