International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The paper presents an informational measurement system for measuring electricity consumption from a three-phase grid during welding of AA6060-T66 aluminium alloy cylindrical workpieces using the TIG (Tungsten Inert Gas) method. In addition to electricity consumption, the developed system can also monitor other related electrical quantities that give an image of the load that the consumer exerts on the grid. The importance of knowing these quantities is reflected in the fact that it can provide us with information about the energy efficiency of the method, as well as the possibility to determine the economic benefits of the chosen process and technology with the knowledge of the welding input parameters. These electricity consumption values affect the sustainability and have an impact on the environment. Energy input also directly affects the quality of the welded joint, which is reflected in penetration, formed microstructure and mechanical properties. Also, knowing this information opens up opportunities to compare performance with other methods. The paper presents the development of such a system, which includes the necessary hardware components, communication and software through which data acquisition is performed.

New area industry of Albania, in recent years, factories with closed cycle of production and processing of aluminium alloys are being targeted. In Albania about 25,000 tons of aluminum alloys per year are produced and there is a tendency to increase this production. This reality has encouraged us to undertake a number of studies with the primary objective for optimizing the parameters of the basic process of this industry. In this article we focus on the process of artificially aging aluminum alloys. From early and newer studies [2], the importance and delicacy of temperature-time parameters in the evolution of microstructure and in the mechanical properties of the final product are recognized and underlined. We have impost an experimental planning based on the Response Surface Method by choosing Central Composite Design to optimize the temperature and time parameters for the artificial aging with the object ive of maximizing the process indicator – mechanical properties, hardness in our case. The plan includes 13 tests with 5 replicas in the center of the experiment, built with the help of Design-Expert DX7 and DX13 software. The focus of our attention was the assesment of the design, analysis of residuals and diagnostic diagrams and forms of presentation of results: mathematical model, 3D response surface, isocontours and effects of interaction between factors. In the future works we will present the experimental results of the optimization of the artificial aging process for different aluminium alloys produced in Albania.

The paper presents the results of research aimed at determining the quality of welds in steel and aluminum alloys. Laser welding technology, fusion-pressure welding in combination with adhesive bonding were used for joining. The present research describes a new bonding technology based on the resistance welding process with a combination of adhesive bonding. Its implementation allows the joining of aluminum and steel sheets at extremely short welding times with a high concentration of energy in combination with adhesive bonding. The quality of the joints was determined on the basis of the tensile shear test according to ISO 12996.

The base process was obtained: 3D hardening temperature field for the K-test under heat transfer at conditions with maximum intensity. A methodology for determining macro-level defects in aluminum alloys. It is definitely the placement of the K-test method in the process of creating the first order phase transition in a casting technology. The idea of interaction between the classical theory of crystallization and quantum mechanics for the processes of structure formation at casting was introduced by Stefan’s task in volume with nano-size.

An aim of a research was to determine the reasons of fracture of aluminium alloy components used for spinning of chemical fibres and to improve spinning process by selecting material with better performance.

The article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. The theoretical part deals with the fatigue and with criteria for evaluation of multiaxial fatigue lifetime, especially Fatemi-Socie, Smith-Watson-Topper, Brown-Miller and Liu. The experimental part deals with testing of specimens for identification of the strain-life behaviour of material and determining the number of cycles to fracture of aluminium alloy for phase shift 0° and 90°. Extensive fatigue experiments were conducted using 6063.T66 aluminium alloy under multiaxial bending-torsion loading.

The article deals with determining of fatigue lifetime of aluminium alloy EN AW 2007.T3 during by multiaxial cyclic loading. The theoretical part deals with the fatigue and with the criteria for evaluation of multiaxial fatigue lifetime, in region low-cycle and high-cycle fatigue. The experimental part deals with modeling of combined bending – torsion loading and determining the number of cycles to fracture in region low-cycle and high-cycle fatigue and also during of loading with the sinusoidal wave form under in phase φ = 0° and out phase φ = 90°.