Dan Florin Nitoi

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.

Semiautomatic High Frequency Ultrasonic Testing System for Welded Plastic Pipes

The present paper proves the feasibility of a semi-automatic control system of high frequency ultrasound for welded plastic pipes, by ultrasonic methods. The paper presents the main existing types of plastic materials, the technological joining possibilities, the problems that may occur in welding and control and the reasoning of the chosen examination method. The theoretical size of the reference ultrasonic parameters for the propagation of ultrasounds through the flawless juncture. The samples were welded using electro fusion (EF) under different working conditions. The samples were assessed circumferentially, every 10 degrees, on different working frequencies. A semi-automatic control system was designed and developed. For the optimal working frequency, a set of 10 measurements was done, in similar working conditions, on the automatic control stand, in order to test the systems’ capability and the results’ repeatability. The measured values were compared with the limits considered to be admissible using Shewhart statistic control charts.

Contributions regarding the use of ultrasound capabilities in the reconditioning by metallization of some automotive parts

Paper presents the ultrasonic energy possibility in the reconditioning by powder metallization process. Three separated ultrasonic methods of energy activation in the deposition metal zone are presented. Advantages and disadvantages are studied for the following technological methods: filler material ultrasonic activation, base material ultrasonic activation, reconditioned metal piece activation, both filler and base material ultrasonic activation. Metallization devices design, are presented according to ultrasonic method activation for the ultrasonic field metallization process using metal powder.

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.