Utjecaj mikrostrukturnih promjena na tribološka svojstva nehrđajućeg austenitnog čeličnog lijeva

undergraduate thesis

• Title (english): Influence of microstructural changes on tribological properties of austenitic cast stainless steel
• Author: Lucia Bratić
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2020-09-24, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Osnovni cilj rada bio je istražiti utjecaj mikrostrukturnih promjena na abrazijsku otpornost
nehrđajućeg austenitnog čeličnog lijeva oznake GX5CrNi 19-10. U teorijskom dijelu rada
navedeni su uvjeti korozijske postojanosti, mikrostruktura, svojstva i podjela nehrđajućih
čeličnih ljevova. Detaljnije su opisani austenitni nehrđajući čelični ljevovi. Također je opisan
abrazijski mehanizam trošenja i utjecaj veličine abrazijskog zrna na gubitak mase pri abraziji. U
eksperimentalnom dijelu rada prikazani su rezultati ispitivanja otpornosti na abrazijsko trošenje i
rezultati mjerenja mikrotvrdoće. Ispitivanje otpornosti na abraziju provedeno je na uređaju Taber
abrader na brusnim papirima kvalitete P220 i P500. Ispitivanje je provedeno na uzorcima sa
100%-tnom austenitnom mikrostrukturom i na uzorcima koji su žareni na 750 °C/1 h, kod kojih
je došlo do porasta austenitnih zrna i do izlučivanja kromovih karbida po granicama zrna.
Utvrđeno je da navedene mikrostrukturne promjene smanjuju tvrdoću i otpornost na abrazijsko
trošenje austenitnog nehrđajućeg lijeva. Također je utvrđeno da se otpornost na abrazijsko
trošenje smanjuje s povećanjem veličine abrazivnih čestica.

Abstract (english)

The objective of this bachelor thesis was to investigate the influence of microstructural changes
on the abrasion resistance of austenitic cast stainless steel grade GX5CrNi 19-10. The general
conditions in which cast stainless steel are corrosion resistant, as their microstructure, properties
and classification were described in theoretical part of the paper. The theoretical focus was given
on describing the austenitic cast stainless steel . During the abrasion process, wear mechanisms
and the influence of the abrasive particle size on the weight loss are also monitored. In the results
section, data obtained from abrasion resistance testing and the microhardness measurements are
presented and explained. Abrasion resistance testings were carried out on a Taber abrader device
on the P220 and P500 abrasive papers. The test was conducted on samples with 100% austenitic
microstructure and on samples heated at 750 °C/1h, which demonstrated an austenitic grain
growth and precipitation of chromium carbides at the grain boundaries. It was determined that
these microstructural changes reduce the hardness and abrasion resistance of austenitic cast
stainless steel. Also, the abrasion resistance decreases with increasing abrasive particle size.

• Keywords: otpornost na abraziju; austenitni nehrđajući čelični lijev; senzibilizacija
• Keywords (english): abrasion resistance; austenitic cast stainless steel; sensitization
• Language: croatian
• URN:NBN: urn:nbn:hr:235:503106
• 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: 2020-09-20 17:07:08