| 摘要 |
PURPOSE:To make on-line measurement of the amount of martensite in a steel plate together with necessary material characteristics, anisotropy, etc. by driving pulselike elastic wave into a steel plate under traveling in a production line, and determining the rates of propagation thereof in the steel plate, or further the elastic constant of an object to be inspected. CONSTITUTION:According to the anisotropic coefft. gammam of a material, the associations of the amount alpha' of martensite, the velocity v of elastic longitudinal waves, and the velocity vt of elastic transverse waves are beforehand measured, and a graph approximating v , vt by the quadratic equation of alpha' is beforehand obtained. Thereafter, elastic pulse waves are propagated in the steel plate under traveling in the line, v , vt are measured, and are collated with the calibration curves of the figure, whereby the amount of martensite in the steel is determined. The alpha'i satisfying v f= <i>(alpha')(i=1-n) and the alpha'it satisfying vt=ft<i>(alpha') are determined from v , and the closest value out of alpha'i and alpha'it is discriminated and is taken as a determined value. On account of the errors in making the calibration curves and the errors of measurement, alpha'i and alpha'it do not agree strictly, but the value sufficiently accurate for practical use is obtained. |
