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Termiškai purkšTų dangų Tyrimas ulTragarsiniais meTodaisJustinas gargasas 1 , irmantas gedzevičius 2 , saulius nagurnas 3 Vilniaus Gedimino technikos universitetas El. paštas: 1 justinas.gargasas@vgtu.lt; 2 irmantas@vgtu.lt; 3 saulius.nagurnas@vgtu.lt santrauka. Straipsnyje pateikiami elektrolankiniu terminio purškimo būdu užpurkštų dangų tyrimai taikant ultragarsinius tyrimų metodus. Purkšta skenuojant besisukančius bandinius 30 cm/s greičiu. Atlikti dangos mikrostruktūros, ultragarsiniai storio, porėtumo, mikrokietumo ir dangos tamprumo modulio tyrimai. reikšminiai žodžiai: terminis purškimas, ultragarsiniai tyrimų metodai, mikrostruktūros, dangos mikrokietumas. research inTo Thermal sprayed coaTings wiTh ulTrasonic meThods J. gargasas, i. gedzevičius, s. nagurnas AbstractResearch on thermal sprayed coatings with ultrasonic methods is the main object of this thesis. Metal surface coating was applied to modify its mechanical and physical-chemical properties and resistance to external impact and improve aesthetics. Spraying was carried out by scanning the rotating sample of 30 cm/s speed. Surface microstructure, ultrasonic thickness, porosity, micro hardness and surface modulus tests performed. Conclusions were formulated. keywords: thermal spray, ultrasound testing, microstructure, micro hardness of coatings.

This paper present the result obtained from new experimental STEIN-MESYFIL 953 V; STEIN-MESYFIL 954 V coatings. The surfacing material was wires of 1.6 mm diameter. The tests aimed at determining wear resistance of coatings sprayed on steel substrate. The investigation shows that the tribological behaviour of new experimental thermal arc sprayed coatings is greatly affected by its microstructural constituents such as porosity, oxide inclusions, and microhardness of coatings. Results show that increasing porosity of coatings twice, it doubles the mass loss. Results for thermal sprayed coatings of all experiments showed their high wear resistance and are discussed.

Santrauka. Straipsnyje nagrinėjama automobilių keliamo triukšmo žala eismo dalyviams ir aplinkiniams, taip pat apžvelgiami Lietuvoje ir Europos Sąjungoje galiojantys dokumentai, reglamentuojantys triukšmo prevenciją ir ateityje įgyvendinamas triukšmo mažinimo priemones. Eksperimentinėje dalyje pateikiama aikštelėje stovinčių automobilių variklių keliamo triukšmo matavimo metodika ir miesto teritorijoje transporto srauto sukelto triukšmo eksperimentiniai tyrimai. Remiantis gautais rezultatais pateikiamos išvados.

In this paper, the use of Fe-base Mn-Si-Cr-Mo-Ni and Fe-base Mn-Si-Cr wires for thermal arc spraying is presented. For this purpose the mechanical and physical properties of coatings were evaluated. The quality of the coating's was dependent on the selected equipment, spray materials, technological parameters of the spray and spray technology. The aim was to qualify and optimize the parameters for spray coating to get the best coatings properties with good tribological properties. All coatings were deposited on mild steel S235JR substrates. Two experimental cored wires of unique chemical composition-STEIN-MESYFIL 932 V and STEIN-MESYFIL 954 Vwere used for thermal arc spraying. The wires of 1.6 mm diameter were used for the surfacing material. Hardness, porosity and oxide measurements were used to verify the spray parameters and analyze the coatings. Rubber wheel test, which is based on the standard ASTM G65, was used. Dry-sand, rubber-wheel procedure according ASTM G65 was used to investigate low stress abrasion, whereas for high stress abrasion investigations a rubber wheel was used. This experiment was carried out by changing the speed of disc friction, travel distance and measuring the mass loss of surface friction. Miller Test according to ASTM G75-95 Standard was carried out in experiment with friction. The samples were immersed in water with corundum and polished with 22 N load, for 8 hours. Furthermore a correlation was performed between the spraying current and voltage parameter. The coatings' cross sections were examined using scanning electron microscope (SEM) and optical microscopy. The influence of the composite components of the coatings' microstructure, such as porosity, microhardness, oxide inclusions, on the tribological properties of thermal sprayed coatings is discussed in this paper.