Analiza mikrostrukture i svojstava ručno kovane mačete

undergraduate thesis

• Title (english): Analysis of microstructure and properties of a hand-forged machete
• Author: Andrija Cestar
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-03-02, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U završnom radu provedena je karakterizacija materijala ručno kovane mačete koja je
uključivala analizu kemijskog sastava, kvalitativnu i kvantitativnu analizu mikrostrukture te
mjerenje mikrotvrdoće.
U teorijskom dijelu rada opisana je povijest kovanja te neka od najpoznatijih oružja dobivenih
kovanjem, kao i podjela postupaka kovanja.
U eksperimentalnom dijelu rada detaljno su opisani parametri postupka ručnog kovanja mačete
za koju je utvrđeno da je izrađena od čelika oznake 55Cr3. U poprečnom presjeku mačete
mikrostruktura se sastoji od bainita i martenzita, a u području oštrice uočena je i mala količina
sitnih karbida po granicama kristalnih zrna. Omjer između volumnog udjela martenzita i bainita
nije isti na svim dijelovima poprečnog presjeka mačete. Razlike u mikrostrukturi i stupnju
ugnječenja odrazile su se na vrijednosti mikrotvrdoće. Najviše vrijednosti mikrotvrdoće
izmjerene su u oštrici mačete (460 – 524 HV0,2). Nešto niže vrijednosti mikrotvrdoće
izmjerene su u tupom dijelu mačete, a najniže vrijednosti mikrotvrdoće izmjerene su u sredini
mačete.

Abstract (english)

In the thesis, the characterization of the material of the hand-forged machete was carried out.
The characterization included analysis of the chemical composition, qualitative and quantitative analysis of the microstructure, and measurement of microhardness.
The theoretical part of the thesis described the history of forging and some of the most famous weapons made by forging, as well as the distribution of forging procesess.
In the experimental part of the thesis, the parameters of the hand-forging process of the machete, which was determined to be made of steel grade 55Cr3, are described in detail. In the cross-section of the machete, the microstructure consists of bainite and martensite. In the area of the blade, a small amount of little carbides was observed at the crystal grain boundaries. The ratio between the volume fraction of martensite and bainite is not the same in all parts of the machete's cross-section. The differences in the microstructure and degree of deformation were reflected in the microhardness values. The highest microhardness values were measured in the machete's blade (460 – 524 HV0.2). Slightly lower microhardness values were measured in the blunt part of the machete and the smallest microhardness values were measured in the middle of the machete.

• Keywords: karakterizacija; mikrostruktura; mikrotvrdoća; kovanje
• Keywords (english): characterization; microstructure; microhardness; forging
• Language: croatian
• URN:NBN: urn:nbn:hr:235:314112
• 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: 2023-02-26 15:32:41