Gheorghe Amza

Ultrasonic System Design and Calculation for Polymer Metallization

Paper presents ultrasonic system design and calculation for metallization process of the polymer pieces. Because of some bad properties like: very low hardness, very low wear resistance, no electrical conductivity and no open fire resistance, polymer parts has to be reinforced with different materials. A new method is represented by ultrasonic field metallization process which has certain advantages. The work presents the analytic calculation for the ultrasonic field and vibration modes of the ultrasonic system used for a polymer base material ultrasonic activation.

Contributions to the Environmental Impact of the Process of Welding Work in the Environment of Protective Gases

Paper presents the main pollutants that appear Gas metal arc welding, the main chemical reactions take place in the melting bath where results the pollutants, determining the impact on the working environment by calculating the coefficient of pollution. The optimization of welding process gives a coefficient of minimum pollution and determines the influence of welding parameters of the system on the appearance of major pollutants elements.

Theoretical and Experimental Cladding Technological Process of Spare Mechanical Engineering

The paper presents the process of cladding surfaces required strong corrosion of parts in the chemical, petrochemical and engineering industry. The phenomenon of the factors that influence the dilution that occurs between the filler material and the base material and the technological processes possible to achieve efficient plating. Following technical and economic analysis establishes that process arc welding argon environment is a process that can be used optimally to plating. It presents experimental results obtained after plating surfaces of parts of the petrochemical industry, the functional characteristics of materials resulting torque in all three major areas (base material, heat affected zone and weld material), structural analysis and possible defects that may occur after the plating process.

Experimental Results Regarding Metal Plating by Welding Method in Ultrasonic Field for High Corosed Base Metal Piece

Paper presents necessity of metal plating in the case of highly corosion process acting on metal pieces. By authors researches, the welding plating method has some disadvantages, possible to be eliminated by using the ultrasonic field. The work presents a series of experimental results obtained in the case of metal plating using welding method [10] with or without ultrasonic field. There were analised the main coupled material resulted functional properties and the final microstructure in the distinctive zone: base material, thermal influenced zone, and addition material.

Influence of the Milling Weld Toe and WIG Remelting Reconditioning Technology to Welded Pieces in the Case of Fatigue Testing

The paper presents the researches to determine the best technologies to improve the lifetime of the corner welding. Generally it is says that the convex corner welding presents high mechanical properties because of the greater area section. The practice activity shows that in fact, because of the stress concentrators, these shapes of the welding are not the best solution. A better shape of the corner welding is the concave one that provides better results in the working conditions. To provide better results of the convex shape corner welding different recondition techniques are known. The paper is focused on fatigue testing performed on different samples realized with different beads on different working parameters. There are studied different reconditioned probes and the results are reported in fatigue curves.

Effect of gaseous impurities and the laser optics

The impurities into the volume of a material appear while the elaboration process of the considered material. If a material is non-homogenous, even if we machine this material by means of a classical technology we could remark some differences in the machining process like cutting, drilling a.s.o. even in the process of welding. The impurities may be gaseous or solid. Each kind of impurity has another effect for the classical tool, or for a non-traditional tool i.e. a kind of concentrated energy. Each kind of medium has another reaction versus laser beam, because each medium has other physical characteristics. The modifications of characteristics require modifications of photon beam parameters. Not any laser equipment is prepared to react correct to any kind of material, representing the impurity. To have a high quality machining process, we must know the nature-kind of the impurity, and in the same time, we must assure such components, which are able to react and correct to all kind of impurities which laser beam will meet. The recently generation of lasers are correct gifted, in order to work with materials presenting all kind of impurities.