TIG welding of nickel super alloy Hastelloy C-22

U ovom su radu analizirane super legure na bazi nikla s posebnim naglaskom na leguru Hastelloy C-22. U teorijskom dijelu dan je njihov pregled, te su grupirane po njihovom kemijskom sastavu i svojstvima. Objašnjeni su postupci zavarivanja legura nikla s posebnim naglaskom na TIG zavarivanje. Opisani su načini pripreme spoja, odabir dodatnog materijala, parametri te zaštitni plinovi za zavarivanje legura nikla. Također opisane su pogreške koje se javljaju prilikom zavarivanja te mikrostruktura zavarenog spoja. U eksperimentalnom dijelu rada opisan je plan zavarivanja super legure Hastelloy C-22 TIG postupkom zavarivanja. Opisana je oprema korištena u eksperimentu, svojstva osnovnog i dodatnog materijala, korišteni zaštitni plin te je izrađena specifikacija zavarivanja (WPS). Analizirana je mikrostruktura osnovnog materijala i metala zavara. Provedeno je elektrokemijsko ispitivanje istosmjernom strujom (DC) osnovnog materijala i metala zavara, te je ispitan njihov kemijski sastav. Rezultati ispitivanja su analizirani, te su izvedeni zaključci o prikladnosti odabranih parametara i izvršenoj pripremi zavarivanja.In this thesis, nickel base superalloys have been analyzed with a special emphasis on the Hastelloy C-22 alloy. In the theoretical part their review is given, and they are grouped by their chemical composition and properties. Welding of nickel alloys with special emphasis on TIG welding is explained. Methods of preparation of the welded joint, selection of additional material, parameters and protective gases for welding nickel alloys are described. Also describe of the errors that occur when welding and microstructure of the welded joint is given. The Hastelloy C-22 TIG welding process is described in the experimental part of the welding of the superalloy. Description of the equipment used in the experiment, the properties of the basic and additional material, the used protective gas and the welding specification (WPS) is given. The microstructure of the basic material and the welded joint was analyzed. Electrochemical testing of DC (DC) of basic material and welded joint was performed and their chemical composition was tested. The test results were analyzed and conclusions were made on the suitability of the selected parameters and weld preparation