초음파법에 의한 스프링강의 재질평가에 관하여

On Evaluation of Material Properties in Spring Steels by Measurement of Ultrasonic Techniques

The general purpose of this paper is Evaluation of material properties in spring steels by investigate correlation between ultrasonic attenuation and virker's hardness, charpy impact properties, microstructures. The three test speciments of the $490{\times}90 mm$ plates and 20 mm thick are used but differ in heat treatment, one is rolled plate, the second is quenched and then tempered, and the third is quenched. ultrasonic attenuation were obtained at fifteen locations on the plates. In order to investigate the correlation between hardness ( especially, HV ) and the attenuation, the virker's hardness and the microstructures were observed for three spring steels. also the charpy impact test were carried out at the room temperature in order to investigate the relationship between impact properties and the attenuation. The experimental results obtained from three different spring related to the heat treatment conditions and attenuation coefficient is increased with increasing the hardness(HV). Ultrasonic attenuation coefficients have shawn are ability to distinguish among spring steels.