Sensitization degree of the austenitic stainless steel welded joints was investigated by electrochemical methods of the double loop electrochemical potentiokinetic reactivation (DL EPR) in H2SO4 + KSCN solution, and by the measurement of corrosion potential of the steel in the drop of the solution of HNO3 + FeCl3 + HCl. The welded joints were tested by X-ray radiographic method in order to check the presence of the weld defects. Grain size of the base metal and the welded joints were determined by optical microscopy. Good agreement between the results obtained by different electrochemical methods was obtained. Heat-affected zone (HAZ) of the austenitic stainless steel welded joints has shown significant degree of sensitization. The double loop electrochemical potentiokinetic method gave quantitative evidence about susceptibility of the stainless steel to intergranular corrosion

The aim of this paper is, improving the characteristic of Ventilation mill for grinding coal which is one of the main part of steam power plants in the system that makes a significant influence on the level of energy efficiency with its work. Working parts of the mil during exploitation are dominantly exposed to intensive abrasive and erosive wear and also to impact loading at elevated temperatures, which can lead to damage and fracture of homogeneous materials, thus shortening their working life. For solving the problem of increasing the wear resistance of the parts for transport and coal grinding in power plants, to investigate the optimum application of technology in hard coatings by different procedures, and filer materials. Hard coatings were carried out with cold (plasma and arc treatment) and hot metallization (with concurrent and subsequent drowning). It has been used the additional materials of different chemical composition and properties based on Ni (NiCrBSi; NiCrBSiFe; NiCrBSi / WC) and Fe (FeCrCSiMo; FeCrCBSiTi; FeCrCBNiSi). The main goal of this paper is to make the selection of optimum hardfacing procedures, group of filler materials and hardfacing technology definition based on the results of structural and mechanical properties of samples, experimental model hardfacing. These were investigation of its structure, measurement and distribution of hardness in the samples, tribology characteristic samples with hard coatings. Based on the results of these tests there were selected the additional materials and procedures for applying hard coatings, which would be apply in the revitalization of parts in transport at and coal grinding.

Rezime U radu je prikazan uticaj zračenja aparata za REL zavarivanje na bezbednost zavarivača i mere bezbednosti i zaštite zdravlja. Razmatran je uticaj svetlosnog, infracrvenog i ultraljubičastog zračenja, kao i uticaj i veličina elektromagnetnog zračenja na pojedine delove tela zavarivača, u toku zavarivanja i u praznom hodu i različitim režimima zavarivanja pri ručnom elektrolučnom postupku zavarivanja obloženom elektrodom (111) na REL aparatima za zavarivanje.