Prednosti navarjanja s strženskimi žicami: Advantages of surfacing with cored wires

Cored wires combine advantages of manual arc welding with covered electrodes and those of semiautomatic and automatic welding processes with solid wires in various shielding media, i.e. gases and fluxes. They are produced in two ways, i.e.: a) by drawing filled-in tubes and b) by folding of a metal strip into a U-form which is to be filled with metals and minerals, and by subsequent shaping of the wire. Cored wires have practically the same diameters as solid wires. Their applicability to welding devices (MIG/MAG and SAW) is equal to solid wires. Cored-wires, however, are very sensitive to the feeding technique of welding machines because there is a risk of opening of the folded wire and of pouring out of the core into the house package, which leads to a nonuniform feeding and finally to a stand-still during welding. Devices for welding with cored wires should have a separate feeding device for wires made of a strip. Owing to a very simple application, cored wires made of a tube are very suitable for welding and surfacing in industry. With a filling ratio of 30% with the above-mentioned wires, very favourable results are obtained also in surfacing of stronger loaded, wear-resistant claddings. Strženske žice združujejo prednosti ročnega obločnega varjenja z oplaščenimi elektrodami s prednostmi polavtomatskh in avtomatskih postopkov varjenja z masivnimi žicami v zaščitnih medijih - plinih in pod praški. Izdelujemo jih po dveh postopkih: a) z vlečenjem polnjenih cevi in b) z zvijanjem traku v žleb, ki ga polnimo s kovinami in minerali, ter nadaljnjim oblikovanjem žice. Strženske žice iz cevi so praktično povsem enakih dimenzij kot masivne. Tudi njihova uporabnost na varilnih napravah (MIG/MAG in EPP) je povsem enakovredna masivnim žicam. Nasprotno pa so strženske žice iz traku zelo občutljive pri pogonu na varilnih strojih, ker obstaja nevarnost odpiranja zavite žice in iztresanja stržena v cevnem paketu (božirju), kar vodi do neenakomernega podajanja in zaustavljanja žice med varjenjem. Naprave za varjenje s strženskimi žicami iz traku morajo imeti poseben pogon. Zaradi zelo enostavne uporabe so strženske žice iz cevi zelo primerne za varjenja in navarjanja v industriji. Z deležem stržena, ki zavzema pri omenjenih žicah okoli 30% preseka, dosežemo zelo dobre rezultate tudi pri navarjanju bolj obremenjenih obrabno odpornih prevlek.