Testing of stress corrosion on samples produced with WAAM technology

U teorijskom dijelu rada opisana su svojstva i zavarljivost dupleks čelika te njihova korozijska postojanost. Opisana je napetosna korozija, mehanizam njezinog nastajanja te metode sprječavanja kod nehrđajućih čelika. Također je opisana aditivna proizvodnja s posebnim osvrtom na proizvodnju čeličnih materijala postupkom aditivne proizvodnje električnim lukom i žicom (WAAM). Objašnjena su zaostala naprezanja koja nastaju pri zavarivanju te metode uklanjanja zaostalih naprezanja kod WAAM postupka. U eksperimentalnom dijelu rada ispitana je tvrdoća uzoraka izrađenih WAAM postupkom. Također ispitana je sklonost napetosnoj koroziji te su provedena elektrokemijska ispitivanja u svrhu ispitivanja korozijske postojanosti uzoraka u usporedbi s dupleks čelikom u isporučenom stanju.The theoretical part describes the properties and weldability of duplex steels and their corrosion resistance. Stress corrosion is also described and the mechanism of its formation and the method of prevention in stainless steels. Additive manufacturing is described with special refrence to the wire and arc manufacturing of steel materials. Residual stress due to welding and method for removing residual stress in the WAAM procedure are explained. In the experimental part, the hardness of the samples made by the WAAM process was examined. The tendency for stress corrosion was also examined and electrochemical tests were performed to test the corrosion resistance of the specimens in comparison with the delivered duplex steel