MEASURING METHOD OF SURFACE ROUGHNESS OF SOLID BY ULTRASONIC WAVE

摘要

PURPOSE:To enable measurement of the surface roughness of a solid by a method wherein a back scattered wave due to roughness of the surface of a substance to be inspected is received by a probe and an echo level thereof is compared with a correlative value of the surface roughness with the echo level of the back scattering wave which is determined beforehand. CONSTITUTION:When a minute indentation 1b exists in a part of the smooth surface 1a of a substance to be inspected, an ultrasonic wave falling on the surface 1a is back-scattered at the part of the indentation 1b due to roughness thereof and a back scattered wave 14 thereof is received by a probe P, while it is reflected specularly on the smooth surface and a reflected wave thereof is not received. An echo level of the scattered wave 14 is compared with a correlative value of the surface roughness with the echo level of the back scattered wave which is determined by measurement with respect to a test piece beforehand, and thereby the surface roughness of the substance 1 to be inspected is measured. Although scanning is made for shifting a position of measurement, subsequently, the surface roughness can be measured on the occasion by scanning in one direction irrespective of a shape, direction, etc. such as the indentation and a stepped part, since the vector of the ultrasonic wave falling on the surface 1a has an equal direction.