TESTING TECHNOLOGY OF THE UNDERCOUPLING SPACE FILLING OF COUPLING ON THE MAIN PIPELINE

Abstract

Background. Now actively used the method of repair with the use of coupling metal structure. It is use to restore the carrying capacity of active pipelines that are working for a long time.
 The coupling is installed on the defective area, and the undercoupling space is sealed and filled under pressure with a self-hardening mass. In this case, the stresses in the pipe walls and coupling are aligned with each other. The parameters of the filling process the undercoupling space determine the quality of the entire coupling repair and require precise testing.
 Objective. The purpose of this article is to analyze the parameters for testing the filling of the under-coupling space using ultrasonic non-destructive testing methods.
 Methods. Strength improvement of the spots of the active pipeline is realized by installing an active main pipeline of couplings. Strengthening the pipeline with the coupling is to redistribute part of the load from the pipe to the wall of the coupling, which leads to a decrease of the stress level in the pipe wall. The reinforcement efficiency of the pipeline could be evaluated by the degree of reduction of circumferential stresses in the wall of the repaired pipe. The article describes the analysis of the possibility of testing the filling of the under-coupling space of the glues-welded and brazed-welded couplings using ultrasonic methods of non-destructive testing.
 Results. The use of the most common piezoelectric transducers is ineffective. This is due to the high temperature of the brazed-welded coupling during working using molten metal, determined by its melting temperature. In this case, it is proposed to use an electromagnetic (EMA) transducer as a radiator and receiver of ultrasonic vibrations. The results of theoretical and experimental studies of the control of filling the undercoupling space of soldered-on sleeves with molten metal have confirmed the effectiveness of using the EMA-method for controlling the formation of the undercoupling space. It is shown that the proposed method of ultrasonic testing allows to achieve maximum efficiency in testing the filling of the brazed-welded coupling with the molten metal.
 Conclusions. The analysis of the possibility of using an ultrasonic method of non-destructive quality control of filling a undercoupling space with a self-hardening substance showed the theoretical possibility of testing the filling of the undercoupling space of glueswelded couplings with both the compounded filling of the undercoupling space and the filling with molten metal.
 The results of experimental studies of the control of filling the under-coupling space of the glues-welded couplings with molten metal using the EMA-method confirmed the effectiveness of using the EMA-method for testing the formation of the undercoupling space.