Spectrum analysis: a new tool for quality control by ultrasonics

This paper presents the results of ultrasonic attenuation measurements performed with spectrum analysis on forged Cr-Ni-Mo steel and on carbon steel produced by continuous casting, both subsequently subjected to various heat-treatment cycles. The measurements have confirmed the possibility of ascertaining structural differences in these steels, even though these may not be immediately evident from metallography, simply by comparing two ultrasonic pulse spectra with an appropriately selected frequency band. These methods of inspection can be applied in industry without any great difficulty.