The immersible quartz--ceramic nozzles produced by the Podolsk Refractories Plant (PRP) for continuous steelcasting machines (CSCM) are important components on the durability of which the stability and smoothness of the continuous process of casting and the character of the crystallization of the steel ingot depend to a considerable extent. The manufacture of the nozzles from quartz glass by slip casting is a labor-intensive and expensive process for which reason it is important that they are quality-tested without the destruction of a certain number for the purpose of obtaining specimens. Such a method would be important because it would permit the testing of all products and not merely a representative sample.The All-Union Institute of Refractories and PRP investigated a nondestructive method of controlling the porosity and density variation of the nozzles for the purpose of determining the influence of the porosity on their service behavior.The porosity of the nozzles was tested by a microwave phase method (using uhf waves) [1, 2]. The method is based on the utilization of the relation between the specific inductive capacitance ~ of the medium and its general porosity P [3]. For quartz ceramic the relation between ~ and P is expressed by the equationwhere 60 is the specific inductive capacitance for a nonporous quartz ceramic (P = 0) and equals 3.81 [5,6].In the phase method of control described here the measured quantity is fl, the advance of the phase of the electromagnetic wave passing through the tested product, i.e., the phase change of the refracted wave caused by its passage through the product. For an inorganic dielectric medium the relation between fi and s is described by the equation [7] = -~-()/~ --1) d.( 2) where s is the length of the electromagnetic wave in free space and d the measurement base (the depth of the examination zone).With regard to Eq. (1), therefore, a well-defined functional relation exists between the advance of the electromagnetic wave and the porosity of the dielectric medium. However, in the case of products like quartz nozzles with their complex configuration and dimensions, the diffraction phenomena may produce a masking effect so that the character of the relation between fl and ~ (P) may differ from that described by Eq. (2).To determine the relation between fi and P in the various examination zones of the quartz nozzles, a comparison and statistical analysis were carried out of the relation between ~ and P in the examination zones of the nozzles. The porosity was determined by the standard method (GOST 2409-67) for specimens prepared from the examination zones. The quantity fi was measured with an INF-2 instrument [8] at wavelength ~ = 3.93 cm using horn antennas with an opening of 2.4 • 2.4 cm. The nozzles were examined in the various zones ( Fig. 1) in the direction of the diametral axis of the plane-polarized wave. The vector of the electric displacement was oriented in the direction of the center axis of the nozzle. The transmission base d was represented by the combi...

In pouring steel from ladles, successful use has recently been made of sliding gate valves in which the crucial elements are refractory slabs [i]o These slabs operate in stringent conditions, and therefore severe technical requirements are imposed on them (TU [2]~ The present quality control of these slabs, which involves testing two specimens from each batch of 400 sets for mechanical strength and open porosity, is inadequate for reliable estimation of the production of crucial components.It is necessary to check each slab separately, as each set has to permit stable pouring of 130-700 tons of steel.In this article we describe the results of investigations on nondestructive quality control of composite (MSP-95) and biceramic (MPB-95) magnesite (peric!ase) slabs .For nondestructive testing of the mechanical properties (open porosity, apparent density, and compressive strength) of refractory artifacts made of dielectric materials, at the All-Union Institute of Refractories (VIO) we have developed a radio-wave phase (uhf) method [3-5] based on measurement of the velocity of transmission of radio waves through the test articles.The method is contactless and permits local monitoring, i.e., measurement of the properties in a limited zone determined by the area of the beam (ray) of electromagnetic radiation.The velocity of transmission of radio waves is measured by means of the phase change of the wave passing through the article relative to that for passage along the same path in air.When radio waves pass through an infinite dielectric medium with low loss (in which the dielectric loss angle tangent is tan ~ < 10-2), the relation between B and the dielectric constant of the medium [6, p. 44] is as follows: 2=where % is the wavelength in free space, in centimeters; c, relative dielectric constant; and d, geometrical path length of the wave in the dielectric medium, in centimeters.We can approximately assume that the radio waves pass through a layer in the articles. Consequently, the relation between B, e, and ~ will take the formwhere r = --4~d ;and ~m is the measured phase lead [7].Since the dimensions of the monitored articles can vary, as the parameter (to be measured by the nondestructive method) by which the properties of an article is to be judged (on the basis of a calibration graph) we choose the corrected phase lead,

The acquisition of automatic manipulators is still not the mechanism and automation of production~ An industrial robot is only a link in a multilink mechanism easing and replacing the labor of man. Therefore, the problem of robotization must be solved in combination in all directions, including the development of presses designed for operation in automated lines, of reliable production proportioning equipment which provides the required accuracy, and of automatic manipulators satisfying the requirements for all characteristics, and the training of medium and high level qualification personnel for servicing and improving the lines.

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