-
Date submitted2022-07-10
-
Date accepted2023-06-20
-
Date published2024-02-29
Mathematical modeling of the electric field of an in-line diagnostic probe of a cathode-polarized pipeline
A mathematical model of the in-line control of the insulation resistance state for cathodically polarized main pipelines according to electrometry data is considered. The relevance of the work is caused by the opportunity to create in-line internal isolation defects indicators of the main pipelines for transported liquids that are good conductors and expand the functionality of monitoring and controlling cathodic protection systems of the main pipelines. Features of the mathematical model are: consideration of the electric conductivity of transported liquid influence on electric field distribution; consideration of the influence of external and internal insulating coating resistance; use of the electric field of an in-line diagnostic probe for quality control of internal insulation. Practical significance consists in the development of modeling methods for control subsystems of main pipeline protection against corrosion and the development of special mathematical and algorithmic support systems for monitoring and controlling the operating modes of the cathodic protection station of main pipelines.
-
Date submitted2019-01-10
-
Date accepted2019-03-02
-
Date published2019-06-25
Modeling of the welding process of flat sheet parts by an explosion
- Authors:
- M. A. Marinin
- S. V. Khokhlov
- V. A. Isheyskiy
The list of materials subject to explosive welding is very extensive and amounts to several hundred combinations of various alloys and metals, and the variety of explosive welding schemes has more than a thousand options. In almost all technical solutions, the process involves the sequential creation of physical contact of the materials to be welded and their connection due to plastic deformation of the contacting surfaces. The strength of such a connection depends on the mode of the welding process. With the correct selection of the parameters of the mode, it is possible to obtain a high-quality connection of the required strength. However, the experimental selection of such options is a very laborious and costly process. Computer simulation and application of mathematical models for solving dynamic problems of explosion mechanics simplifies the search for optimal parameters and allows to predict the expected result in the shortest possible time. The article discusses the issues of modeling of explosive welding of metals, calculations related to the parameters of the process of formation of the weld using the Ansys Autodyn software package. A model is presented for analyzing the deformation process of explosion welding of a plate and its connection with a matrix. The main parameters of explosion welding (velocity, pressure, time) are determined. The adequacy of the obtained values was evaluated in the systems aluminum – copper and copper – steel. It also provides a comparative analysis of simulation results and field experiments. Based on numerical calculations, a conclusion was substantiated on the suitability of the model obtained for a preliminary analysis of the main welding parameters at the preparatory stage.
-
Date submitted2017-08-30
-
Date accepted2017-11-23
-
Date published2018-02-22
Basic provisions and problems of ELW technology for the manufacture of aluminum-magnesium alloys constructions
- Authors:
- E. I. Pryakhin
- N. I. Sharonov
Existing problems of electron beam welding of aluminum alloy constructions are considered. For research purposes, the aluminum-magnesium alloy of grade 1561 up to 60 mm thick was used. The thermal field in the heat influence zone is studied experimentally and analytically on the basis of the finite element method (the «Ansys» program). The effect of electron beam movement (scanning) influence on the quality of welded connections and the surface of the welded parts was studied. On the basis of metallographic studies and mechanical tests of welded metal, it is proved that high quality of welded joints is ensured when the beam moves along a curve of the «compressed brackets» shape. A special generator is designed to control the electron beam, which allows to implement a new type of scanning (compressed brackets). The fundamentals of welding technology for alloy 1561 up to 60 mm thick are outlined. Specific recommendations are given, and two new methods are proposed that will allow the successful use of the developed technology in factories in the production of new products and in the repair processes. Examples and analysis of thermal cycles obtained by calculation and experimental method are given. The patterns of heat distribution along the trajectory of the beam movement for different types of scanning are established. The main types of defects in the formation of the welded joints and those formed in the metal during crystallization are considered. Their interrelation with the parameters of the welding mode is shown.
-
Date submitted2010-07-07
-
Date accepted2010-09-06
-
Date published2011-03-21
Improvement of quality of dissimilar welded joints made of pipelines steels by application of vibromechanical treatment in welding
- Authors:
- O. F. Khafizova
The article describes opportunity of improvement of physical-mechanical properties of welded joint made of different strength grade pipeline steels (Steel 20 of K42 strength grade and 16ГС – K52) by applying vibration during the welding cycle. It’s shown that maximal positive effect is achieved by vibration frequency approximating to natural-vibration frequency of welded construction.
-
Date submitted2010-07-15
-
Date accepted2010-09-13
-
Date published2011-03-21
Experimental setup for research Influence of vibromechanical treatment on mechanical properties of welded joints
- Authors:
- O. F. Khafizova
- V. I. Bolobov
The description of developed experimental setup for welding product that made of pipeline steels with application of applying vibration with intended frequency approximating to natural-vibration frequency of welded construction unit of pipelines during the welding cycle is presented.
-
Date submitted2009-09-25
-
Date accepted2009-11-15
-
Date published2010-06-25
Studies of resistance micro-welding modes for dentistry applications
- Authors:
- A. B. Tsyganov
- A. S. Mustafaev
Various modes of resistance welding between steel and Ni-Ti-extracting electrodes and fractures of endodontic files were investigated. It was demonstrated that in close to real clinical situations there is most suitable a sequence of a number of pulses of a steepened welding current. As a result, detachment force limit of 15-50 N is achievable which is sufficient for the fracture extraction in most cases.