A nondestructive acoustic sonic method of inspection for certification of finished refractory parts

Abstract

UDC 666o762o!6o017:620.~!!.~ Recently the nondestructive (sonic) method has obtained ever increasing use in inspec tion of the quality of refractory parts. The use of this method under plant conditions makes it possible to increase the number of inspected parts without limit, which in the final analysis provides an objective evaluation of production quality.The use of the nondestructive method of inspection of the quality of finished production makes it possible:to increase labor productivity in inspection operations; to accelerate the inspection process; to save refractories as the result of those saved in nondestructive inspection; to improve sanitary and technical working conditions.The nondestructive method of inspection of the quality of finished refractory parts was developed by the All-Union Institute for Refractories [i, 2]. This method is based on establishment of a correlation relationship between the weight of a part and the frequency of its natural vibrations and also the open porosity, apparent density, and compressive strength.The experimental data were processed using a program in three stages.The program for the method was developed in Fortran language for EC computers in the Laboratory for Applied The original data are prepared for calculation of the full polynomial from two second power variables (that is, the values of m 2, f2, mf, f are calculated from sample data) and each of the variables is considered as optional for inclusion.The significance was verified at the 0.05 level, that is, the level of reliability is 95%.As the result of operation of the program an equation is produced which is considered suitable only if it contains terms only linear with respect to m and f (does not contain the terms m 2, f2, mf) and inclusion in the equation of the variable is necessary.If only the variable m is included in the equation, it is also unsuitable.

The potential for nondestructive testing of refractories

“…The resonance (acoustic) method has been used industrially in connection with the known correlation between resonance frequency of a freely oscillating article fp and its working properties* [12,13]. The method evaluates the integral properties of the articles based on the use of known physical phenomena -change in the tone of the sound, vibration in the presence of defects, and structural variations.…”