Zoran Kožuh

Sensors and their classification in the fusion welding technology

In this paper the most commonly used sensing systems in modern welding industry, which nowadays includes robotic systems, are listed and analyzed. According to mechanisms of action and measured parameters, several classifications of sensor systems have been presented. MIG/MAG, resistance and laser beam welding processes are the most commonly robotized ones in the industry and therefore special attention has been given to them. Several characteristic, limitations and advantages of sensor systems are presented and mechanisms of action are briefly described.

Determination of clad plates residual stresses by x-ray diffraction method

The paper elaborates the influence that clad procedure has on the level and nature of residual stresses in clad plates. There are three clad procedures applied, as follows: hot rolling, submerged arc welding (SAW) with strip electrode in two layers and explosion welding. Theoretical basics on residual stresses measured by x-ray diffraction are reviewed in the paper, with special emphasis put on problems of underclad cracking tendency. In all applied cladding procedures, usage of heat treatment by anealing resulted in the decrease of residual stresses values. However, transformation of commpresed stresses into tensile stresses in some cases was very unfavourable, if referring to the tendency of plating corrosion resistant steel to stress corrosion and to underclad cracking.

Mathematical model for calculation of thickness of flame sprayed coating of aluminium on S235JR steel

Abstract In the present work, the method of response surfaces was employed for the purpose of drawing up a mathematical model for the calculation (forecasting) of the thickness of a flame sprayed coating of powdered aluminium on S235JR steel. Experimental work was conducted according to a full central composite design at three levels. The thickness of the coatings made with combinations of input parameters of the procedure according to the experiment plan mentioned was measured in line with the ISO 2064 standard. A mathematical model was derived describing the dependence of the experimentally obtained thickness values on the input parameters of the procedure. The possibility of analysing the influence of the parameters upon the thickness for a certain combination of input parameters has been presented with the use of perturbation plots.

A Mathematical Model for the Calculation of the Adhesion of a Flame Sprayed Coating of Aluminum on S 235 JR Steel

In this work the method of response surfaces was used for the purpose of drawing up a mathematical model for the calculation (forecasting) of the adhesion of a flame sprayed coating of powdered aluminum on S 235 JR steel. Experimental work was conducted according to a fractional central-composite design at three levels. The adhesion of the coatings made with combinations of input parameters of the procedure according to the experiment plan mentioned is measured in line with the EN 582 standard. A mathematical model was derived describing the dependence of the experimentally obtained adhesion values on the input parameters of the procedure. The possibility of analyzing the influence of the parameters on the adhesion for a certain combination of input parameters has been presented with the use of perturbation plots.

Properties of aluminium coatings produced using manual and robotized flame spraying processes

Abstract Aluminium coatings applied using arc or flame spraying processes are frequently employed for protection of steel structures in maritime applications. Results of comparative testing of aluminium coatings produced by manual and robotized flame spraying on steel substrate are reported in the contribution. Particular attention during the investigation of coating properties has been given to the uniformity of coating thickness, adhesion and corrosion resistance. Analysis of the results yielded conclusions on the quality, adhesion and corrosion resistance of the aluminium coating when the coating is applied to the flat steel plate.