Analiza nastanka toplih pukotina pri zavarivanju raznorodnih čelika

master's thesis

• Title (english): Analysis of hot cracking appearance during welding of dissimilar steels
• Author: Marko Bajs
• Mentor: Ivica Garašić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Tema ovog diplomskog rada je: „Analiza nastanka toplih pukotina pri zavarivanju raznorodnih čelika“. Sastoji se od dva dijela, teoretskog i praktičnog. U prvom dijelu rada prikazane su opće značajke MAG zavarivanja poput parametara te načina prijenosa metala. Analizirani su nelegirani i visokolegirani čelici, mehanizmi nastanka toplih pukotina te su opisane metode ispitivanja osjetljivosti zavarenih spojeva na pojavu toplih pukotina. Objašnjen je utjecaj zaostalih naprezanja, nečistoća poput sumpora, stupnja miješanja kao i udio ferita u metalu zavara. U eksperimentalnom dijelu rada za kombinaciju osnovnih materijala nelegiranog i visokolegiranog čelika odabrana je prikladna metoda ispitivanja toplih pukotina te su definirani parametri zavarivanja. Prilikom izvođenja eksperimenta obuhvaćeno je više razina unosa topline, načina prijenosa metala u električnom luku i oblikovanje zavarenog spoja. Na temelju analize provedenih ispitivanja definirane su kritične vrijednosti varijabli obzirom na pojavu toplih pukotina.

Abstract (english)

The theme of this diploma thesis is: "The analysis of the occurrence of hot cracks in welding dissimilar steels." It consists of two parts, theoretical and practical. The first part shows the general characteristics of MAG welding parameters as well as methoda of metal transfer. In this thesis unalloyed and high alloyed steels and mechanisms of hot cracks are analyzed and welds sensitivity testing methods to examine the occurrence of hot cracks are described.The influence of residual stresses, impurities such as sulfur, dilution as well as the proportion of ferrite in the weld metal are also explained. In experimental section of this thesis for combination of basic non-alloy and high alloy steel materials appropriate hot cracks test method is selected and welding parameters are defined. Experiment included several levels of heat input, their transmission metal in an electric arc and weld design. Based on the analysis of the tests performed,critical values of the variables for the occurrence of hot cracks are defined.

• Keywords: tople pukotine; udio ferita; raznorodni čelici; MAG zavarivanje
• Keywords (english): hot cracks; ferrite content; dissimilar steels; MAG welding
• Language: croatian
• URN:NBN: urn:nbn:hr:235:789598
• 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: 2019-05-22 13:42:49