Table of Contents


    • Tribological properties of layers created by progressive technologies

      pg(s) 296-299

      The paper presents the results of research focused on the renovation of worn surfaces. Four progressive welding technologies were used – Cold Metal Transfer, MIG Pulse, TOP-TIG and laser technology. The layers were evaluated by non-destructive tests – visual, capillary and ultrasonic methods. The layers were evaluated under dry-friction adhesive wear conditions by the Ball-On-Disc method. A Si3N4 bead was used. Analyzes confirmed the impact of the renovation method on the quality of the resulting surface.

    • Selection of welding technology for AA6060 aluminum alloy tubes using economic analysis

      pg(s) 300-303

      This paper presents a method of economic analysis of welding tubes made of aluminum alloy AA6060 using MIG and TIG arc processes, as well as the non-conventional FSW process in relation to the length of the welded joint. The cost model includes fixed and variable costs, which are broken down into individual components, and their specifics for each of the selected processes are considered. The input values were defined and a calculation was made for obtaining a specific workpiece, that is, for welding a tube with an outer diameter of ∅150 mm, and a wall thickness of 5 mm, with a butt joint in real production conditions. The obtained results were analyzed and the price of welding was determined according to the production time and per meter of the welded joint.

    • Investigation of the energy-power parameters of forging process in step-wedge strikers

      pg(s) 304-306

      In this paper the deformation force of the forging process in step-wedge strikers was studied. At the first stage, the study of the deformation force using computer modeling in the Deform-3D software package was carried out. At the second stage, an experimental study of the deformation force during the broaching of workpieces in step-wedge strikers using thermometry was carried out. It is established that the experimental results have a high convergence with the simulation values. The increasing level of difference in results is associated with heat losses during intermediate operations, which are usually ignored during modeling.

    • Financial project for building a technological line and factory for the production of yellow pavers, tiles and other products

      pg(s) 307-314

      A financial project was presented for the construction of a technological line for the production of high-quality replicas of the socalled “yellow paving stones” and an additional assortment of products with different characteristics based on raw materials originating in Bulgaria. After many years of investigation in laboratory and semi-industrial conditions, polycomponent formulations and an original hightemperature technological regime for the preparation of functional and long-lasting silicate products have been developed. The planned technological approach is in accordance with the existing machine park and the qualification of the industrial production personnel, characteristic of the silicate industry. The main possibilities for the realization of the production are the full restoration of the street areas of the central historical part of Sofia and the construction of long-lasting and aesthetic pavements with a variety of functional purposes in different areas of the capital and other populated areas. The current applied development is oriented towards possible potential producers and investors and various specialists from the field of public infrastructure and cultural-historical heritage.

    • Further development of the possibility of creating composite coatings from ash microspheres on a steel basis

      pg(s) 315-317

      The article is devoted to the solution of an important scientific and technical problem of development of new composite coatings with the use of industrial waste of thermal power plants – aluminosilicate empty microspheres. The analysis of existing technologies showed the prospects for the use of electric arc spraying, which will expand the scope of compositions. All-drawn wires of ER346 (Св-08) and 1066 (65Г) brands were used for coating, ash fillers of aluminosilicate composition were used as fillers. The effectiveness of ash microspheres for the formation of coatings is confirmed by the results of hardness measurements. Coatings filled with ash microspheres have increased Vickers hardness by 7… 22%. The use of ash slags in new technologies is a promising practical area, the implementation of which will help in the search for scarce minerals.

    • Desktop Information System for Employee Management

      pg(s) 318-320

      The report presents a developed Desktop Information System for Employee Management. The system includes database development and encryption using a special algorithm to create an encryption key. The main goal of the development is to provide two types of protection: at the entrance to the system and in the transmission and data storage. The system includes four access levels: Employees, Executives or Managers, Directors and Administrators.
      The information system includes the following functionalities, depending on the access levels: entering tasks, registering users, entering priorities for tasks, entering the status of tasks, reviewing entered tasks, editing tasks and their status, deleting tasks, reviewing , add, edit and delete all users in the system; and others.

    • Digital art. Implementation features with the help of software and communication technologies

      pg(s) 321-323

      Modern communication and digital technologies allow us to talk about digital art as a separate concept with a complex structure.
      Communication technologies combine the individual components of digital art into a single whole. Modern digital technologies contribute to the implementation of creative ideas, promotion and implementation of projects in the field of art. The technologies used in this area have their own characteristics.

    • Hybrid technologies for joining dissimilar materials

      pg(s) 324-326

      This paper presents an overview of hybrid technologies for joining dissimilar materials in automotive applications. CMT welding/brazing technology has been experimentally verified for the purpose of joining dissimilar steels or steels and aluminium alloy. Two types of filler material were used, one based on Cu and the other based on Al. When joining dissimilar steels, a true brazed joint was formed, while when joining steels and aluminium, a hybrid – welded/brazed joint was formed. Subsequently, metallographic analysis of the joints and testing of their load carrying capacity was carried out.