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Pregled literature kaže, da še ni enotno priznane razlage za proces napetostne korozije. Zaradi tega in kompleksnosti napetostne korozije pa je tudi zahtevno določiti dobo trajanja konstrukcij, izpostavljenih napetostno korozijskemu pokanju. V zadnjem času se je pojavila nova metoda določevanja t.i. korozijske krivulje raztezanja, ki omogoča te vrste napovedi. Z njeno modifikacijo nam je uspelo natančno določiti primarno, sekundarno in terciarno področje. Na osnovi odvisnosti log i$_ss$-log t in log sigma-log t so bili konstruirani obratovalni diagrami, ki dajejo možnost napovedi časa do nastanka razpoke, njene stabilne rasti in časa do zloma materiala. Poznanje laboratorijskih rezultatov in korelacija teh s podobnimi iz prakse omogoča uporabo obratovalnih diagramov za napoved dobe trajanja vitalnih delov strojne opreme ter drugih konstrukcij v različnih vejah industrije. A survey of the literature has shown that there is no clear or accurate definition of stress corrosion cracking processes. Because of this and because of the complexity of these processes, it is very difficult to determine the lifetime of metallic materials when exposed to stress corrosion cracking. Over the last few years a new method for defining corrosion elongation curves has been developed, on the basis of which such lifetimes can be predicted. Using various modifications of this method, it is possible to determine accuratelt the primary, secondary and tertiart regions of corrosion elongation curves. On the basis of experimentally-determined relationships between log i$_ss$, and log sigma, on the one hand, and log t, on the other hand, working diagrams have been constructed from which it is possible to predict the time to crack initiation, the time of the crack's stable growth, and the time to failure of the material. Based on the results of laboratory tests, and the correlation of these results with those obtained in practice, such working diagrams can be used to determine the lifetime of vital parts of machinery and other structures in various branches of industry. |
