Karakterizacija materijala tribološki oštećenog zupčanika

master's thesis

• Title (english): Materials characterization of tribological damaged gear
• Author: Mihaela Ljubek
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Cilj ovog rada bio je utvrditi uzrok prebrzog tribološkog oštećivanja zupčanika izuzetog iz
stroja za proizvodnju vreća za pakiranje cementa.
U teorijskom dijelu rada opisani su zupčanici i glavni uzroci njihova dotrajavanja. Navedeni su
i opisani čelici koji se najčešće koriste za izradu zupčanika i toplinske obrade koje se
primjenjuju za postizanje optimalnih svojstava.
U eksperimentalnom dijelu rada provedena je analiza kemijskog sastava, analiza mikrostrukture
i mjerenje mikrotvrdoće oštećenog zupčanika.
Zupčanik je izrađen od ugljičnog čelika s masenim udjelom ugljika od ≈ 0,5 %. Mikrostruktura
čelika sastoji se od ferita (56 %) i perlita (44 %), a ista je na ruba zuba i u jezgri zupčanika.
Mikrotvrdoća uz površinu bokova zubi je relativno niska i iznosi 228 HV0,1, a mikrotvrdoća u
jezgri je još niža i iznosi 144 HV0,1. Prema svemu navedenom uzrok preranog trošenja bokova
zubi analiziranog zupčanika je izostanak odgovarajuće toplinske obrade koja bi dovoljno
povisila tvrdoću i otpornost na trošenje.

Abstract (english)

The aim of this work was to determine the cause of too fast tribological damage of gears
excluded from the machine for the production of cement packing bags.
The theoretical part of the paper describes the gears and the main causes of their wear. The
steels most commonly used for gear fabrication and heat treatment that are applied to achieve
optimal properties are listed and described.
In the experimental part of the work, the analysis of chemical composition, analysis of the
microstructure and measurement of microhardness of the damaged gear were performed.
The gear is made of carbon steel with a carbon content of ≈ 0.5%. The microstructure of steel
consists of ferrite (56%) and perlite (44%) and it is the same at the tooth edge and in the gear
core. The microhardness along the surface of the flanks of the teeth is relatively low and
amounts to 228 HV0.1, and the microhardness in the core is even lower and amounts to 144
HV0.1. According to all the above, the cause of premature wear of the flanks of the teeth of the
analyzed gear is the lack of appropriate heat treatment that would sufficiently increase the
hardness and wear resistance.

• Keywords: zupčanik; tribološko oštećenje; karakterizacija
• Keywords (english): gear; tribological damage; characterization
• Language: croatian
• URN:NBN: urn:nbn:hr:235:252997
• 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: 2021-07-13 15:52:16