Određivanje kritičnog unosa topline za primjenu korijenske zaštite kod TIG zavarivanja Cr-Ni čelika

undergraduate thesis

• Title (english): Determination of critical heat input for application of back shielding at TIG welding of Cr-Ni steel
• Author: Bruno Bauer
• Mentor: Ivica Garašić (mentor)
• Committee member: Ivica Garašić (predsjednik povjerenstva)
• Committee member: Tomislav Staroveški (član povjerenstva)
• Committee member: Vinko Šimunović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-02-25, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom je radu obrađena problematika TIG zavarivanja nehrđajućih čelika bez korijenske
zaštite. Svrha rada je odrediti iznos unesene topline za koji nije potrebna korijenska zaštita.
Rad se sastoji od dva dijela teorijskog i praktičnog.
U teorijskom dijelu opisan je TIG postupak s posebnim naglaskom na tehnologiju zavarivanja
visokolegiranih austenitnih Cr-Ni čelika, opremu potrebnu za uspješnu primjenu i parametre
zavarivanja. Opisan je značaj korijenske zaštite i zaštitni plinovi koji se koriste za korijensku
zaštitu. Proučavani su zahtjevi norme HRN EN ISO 15614-1 koji definiraju primjenu
korijenske zaštite.
U eksperimentalnom dijelu provedeno je automatizirano TIG navarivanje uzoraka izrezanih iz
cijevi od nehrđajućeg čelika AISI 304 s različitim unosima topline. TIG navarivanje izvodilo
se bez primjene korijenske zaštite. Nakon vizualne kontrole izrađeni su makroizbrusci na
kojima se vidi poprečni presjek navara. Proučavane su geometrijske značajke i obojenja
površine materijala s korijenske strane za pojedine razine unosa topline. Povećanje unosa
topline utjecalo je na povećanje geometrijskih značajki navara. Kod najmanjeg unosa topline
pojavilo se obojenje površine materijala s korijenske strane što ukazuje na potrebu za
korijenskom zaštitom iako je debljina podloge bila veća od 5 mm za koju prema normi HRN
EN ISO 15614-1 nije potrebna korijenska zaštita.

Abstract (english)

This paper deals with the problem of TIG welding on stainless steels without root protection.
The purpose of this work is to determine the amount of heat input for which no root
protection is required. The paper consists of two parts, theoretical and practical.
The theoretical part describes the TIG process with special emphasis on the welding
technology of high-alloyed austenitic Cr-Ni steels, the equipment required for successful
application and the welding parameters. The significance of root protection and shielding
gases used for root protection are described. The requirements of the HRN EN ISO 15614-1
standard defining the application of root protection have been studied.
In the experimental part, automated TIG bead on plate welding of AISI 304 stainless steel
tube with different heat inputs was performed. TIG welding was performed without the
application of root protection. After visual inspection, macrographs were made on which the
cross-section of the weld can be seen. The geometrical characteristics of the weld crosssection
and heat tints on the root side of the material were studied for different heat input
levels. The increase in heat input affected the increase in the geometrical characteristics of the
welds. At the lowest heat input, heat tints on the root side surface of the material appeared,
which indicates the need for root protection, although the thickness of the material backing
support was greater than 5 mm, for which root protection is not required according to HRN
EN ISO 15614-1.

• Keywords: TIG; nehrđajući čelici; automatizirano navarivanje; korijenska zaštita.
• Keywords (english): TIG; stainless steels; automated welding; root protection.
• Language: croatian
• URN:NBN: urn:nbn:hr:235:958972
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-02-25 16:36:04