Utjecaj parametara AC TIG zavarivanja na mikrostrukturu P91 čelika

master's thesis

• Title (english): Influence of AC TIG welding parameters on microstructure of P91 steel
• Author: Mislav Škrtić
• Mentor: Ivica Garašić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-12-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Production Mechanical Engineering

Abstract

U teorijskom dijelu rada dan je pregled metalnih materijala za rad pri visokim temperaturama. Opisane su promjene koje se događaju u čelicima uslijed rada pri visokim temperaturama. Detaljno su opisane karakteristike visokolegiranog martenzitnog čelika P91 koji se primjenjuje u izgradnji termoenergetskih postrojenja. Obrazložena je problematika zavarivanja čelika P91, opisane mikrostrukturne transformacije u zoni utjecaja topline i mehanizmi nastanka pukotina. Prikazani su najčešće korišteni postupci zavarivanja s posebnim naglaskom na primjeni TIG postupka zavarivanja.
U eksperimentalnom dijelu rada provedeno je ispitivanje utjecaja parametara TIG postupka zavarivanja izmjeničnom strujom na geometriju i svojstva zavarenog spoja čelika P91. Nakon postupka pretaljivanja, za svaki ispitni uzorak utvrđen je unos topline. Ispitni uzorci su podvrgnuti analizi mikrostrukture i mjerenju tvrdoće. Na temelju analiziranih podataka dobivenih ispitivanjem, doneseni su zaključci o primjeni TIG AC postupka zavarivanja čelika P91.

Abstract (english)

In the theoretical part of the paper, an overview of high temperature metallic materials is given. The changes that occur in steels due to the high temperature operation are described. The characteristic features of high-alloy martensitic steel P91 used in construction of thermal power plants are described in detail. The weldability of steel P91 is explained, microstructural transformations in the heat affected zone and the mechanisms of crack formation are described. The most commonly used welding procedures are presented with special emphasis on the application of TIG welding process.
In the experimental part of the paper, the influence of parameters of the TIG AC welding process on the geometry and properties of the welded joint of steel P91 was investigated. After the welding procedure, heat input for each test sample was determined. The test specimens were subjected to microstructural analysis and hardness measurement. Based on the analyzed data obtained by testing, conclusions were made on the application of TIG AC welding procedure of steel P91.

• Keywords: čelik P91; balans izmjenične struje; frekvencija izmjenične struje
• Keywords (english): P91 steel; alternating current balance; alternating current frequency
• Language: croatian
• URN:NBN: urn:nbn:hr:235:839281
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-12-08 09:56:04