ON THE ACOUSTIC PARAMETERS OF METAL CONSTRUCTIONWHEN DAMAGE IS ACCUMULATED

In the work with the use of nondestructive control methods, the issues of determining acceptable durability or safe resource are considered. It is shown that the design monitoring procedure can be presented as follows: determines the original state zero zone, where the material of the product was subjected to low operational loads; further, with the use of nondestructive control methods, the acoustic parameter is measured (without disassembling the product)., such as the speed of elastic acoustic waves, nonlinear acoustic parameter, difference of velocities with twofrequency sensing, etc.; acoustic scanning of the product's metal is performed, in areas where there have been significant loads, signoff voltages, leading to an intensive accumulation of damage (the destruction of metal leading to cracks); defined zone “N” where the metal state parameter, for which the value is taken, characterizing the difference of the acoustic parameter (the speed of elastic waves, nonlinear acoustic parameter, the difference in velocity in twofrequency sensing) relative to the same parameter in the zone of zero exceeds the established level. The regularities established in the work linking the presence of plastic deformation with the difference in the delays (velocity) of elastic Rayleigh waves at different sounding frequencies at a fixed base between the emitter and the receiver of elastic waves, as well as the behavior of a nonlinear acoustic parameter during the safe resource time, suggest the possibility of using the observd fact as a principle for controlling the limiting state of the material due to plastic deformations on industrial structures. Based on the proposed approach, an engineering methodology for determining the technical condition of the material of the structures of production facilities is proposed, which allows to establish three stages of operation: the reliable operation mode; the controlled operation mode and the critical operation mode.

QUALITY SUPPORT OF PARTS MANUFACTURED BY MEANS OF ADDITIVE TECHNOLOGIES

On this account the purpose of this work became quality parameter support of products obtained with the aid of 3D-printing. By the authors there was carried out a series of investigations on samples manufactured on the Ultra 3 3D-printer of the Envision Tec. Company. The samples were manufactured in batches of seven samples in each. Each sample from the batch varied from each other with the growth angle α between the researched surface and a “contact window”, and also the thickness of the layer z. With the aid of the profile meter TR110 there was measured roughness and for a thorough analysis of roughness step dimensions there was used a probe microscope of SolverPro company operating in the mode of atomic-power microscopy. The data analysis helped to draw a conclusion on the nature of roughness formation at prototyping, and digital data obtained were accumulated in a table and with the aid of statistical processing there was deduced an equation of the roughness parameter dependence of the surface Ra upon initial technological parameters of the prototyping process. But further roughness improvement can be achieved with the combined shaping with the aid of additive technologies and further machining carried out on a single platform. Investigation methods: at the heart of the work underlie experimental methods of investigation. The investigations are carried out with the use of modern means of nondestructive control; with the use of methods of probe microscopy and standard methods of roughness measurement with the use of a profile meter. The processing of investigation results is carried out with the use of modern mathematical apparatus. Work novelty: there is defined the nature of roughness formation on the surface of a product manufactured with the aid of additive technologies at technological parameter variation of prototyping.

Status of nondestructive control of transport function metal products at JSC EVRAZ NTMK

Achievements in the area of automated ultrasonic control of quality of rails, solid-rolled wheels and tyres, wheels magnetic powder crack detection, carried out at JSC EVRAZ NTMK. The 100% nondestructive control is accomplished by automated control in series at two ultrasonic facilities RWI-01 and four facilities УМКК-1 of magnetic powder control, installed into the exit control line in the wheel-tyre shop. Diagram of location, converters displacement and control operations in the process of control at the facility RWI-01 presented, as well as the structural diagram of the facility УМКК-1. The automated ultrasonic control of rough tyres is made in the tyres control line of the wheel-tyre shop at the facility УКБ-1Д. The facility enables to control internal defects of tyres in radial, axis and circular directions of radiation. Possibilities of the facility УКБ-1Д software were shown. Nondestructive control of railway rails is made at two facilities, comprising the automated control line of the rail and structural shop. The УКР-64Э facility of automated ultrasonic rails control is intended to reveal defects in the area of head, web and middle part of rail foot by pulse echo-method with a immersion acoustic contact. The diagram of rail P65 at the facility УКР-64Э control presented. To reveal defects of the macrostructure in the area of rail head and web by mirror-shadow method, an ultrasonic noncontact electromagnetic-acoustic facility is used. It was noted, that implementation of the 100% nondestructive control into the technology of rolled stuff production enabled to increase the quality of products supplied to customers and to increase their competiveness.

NONDESTRUCTIVE CONTROL METHOD OF BUILDING CONSTRUCTIONS

In work the way of the solution of an engineering task of determination of length of piles as a part of a grillage is considered.