Utjecaj brzine deformacije na tvrdoću materijala u procesu sabijanja u hladnom stanju

master's thesis

• Title (english): Impact of deformation rate on the hardness of the material in the cold upsetting process
• Author: Josip Šokec
• Mentor: Zdenka Keran (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-07-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Production Mechanical Engineering

Abstract

U ovom radu opisano je sabijanje aluminijskih i bakrenih valjčića na hidrauličnoj preši i
gravitacijskom batu, te utjecaj sabijanja (hladne plastične deformacije) na tvrdoću metalnog
materijala. Opisani su osnovni principi oblikovanja metala deformiranjem kao što su temeljni
zakoni deformiranja, plastično tečenje materijala i mehanizmi očvršćivanja materijala. Također
naglasak je stavljen i na vrstu te brzinu gibanja dislokacija, opis smjera i dimenzija gibanja
dislokacija te gustoću dislokacija.
U eksperimentalnom dijelu rada sabijeni su aluminijski i bakreni valjčići prvo na
gravitacijskom batu pa na hidrauličnoj preši. Sveukupno je obavljeno po 5 sabijanja valjčića
radi postizanja različite visine sabijanja na svakom od strojeva. Nakon sabijanja mjerila se
tvrdoća uzoraka kako bi se pokazao utjecaj stupnja deformacije na tvrdoću. Svi rezultati
prikazani su tablično i grafički. S obzirom na razliku u brzini deformiranja na batu i na preši,
napravljena je usporedba promjene tvrdoće materijala u ovisnosti o brzini deformiranja.
Koristeći MSC Marc Mentat program napravljena je simulacija sabijanja kako bi se utvrdio
raspored naprezanja i utjecaj različite brzine deformacije na raspored i iznos naprezanja
pojedinog materijala. Također uspoređeni su rezultati na hidrauličnoj preši i gravitacijskom
batu.

Abstract (english)

This thesis describes the compression of aluminum and copper cylinders using a hydraulic press
and a gravity drop hammer, and the influence of compression (cold plastic deformation) on the
hardness of the metal material. The basic principles of metal forming are described, such as
basic laws of deformation, plasticity of materials and mechanisms of material hardening.
Emphasis is also placed on the type and speed of dislocation movement, description of the
direction and dimensions of dislocation movement and dislocation density.
In the experimental part, aluminum and copper cylinders were compressed first on a gravity
drop hammer, and then on a hydraulic press. A total of 5 cylinder compaction were performed
in order to achieve a different compaction height on each of the machines. After compression,
the hardness of the samples was measured to show the influence of the degree of deformation
on hardness. All the results are presented in tables and graphs. Considering the difference in the
speed of deformation on the gravity drop hammer and hydraulic press, a comparison was made
of the change in hardness of the material depending on the speed of deformation.
Using the MSC Marc Mentat program, a cylinder compression simulation was conducted to
determine the stress distribution and the influence of different strain rates on the distribution
and amount of stress of a particular material. The results on the hydraulic press and on the
gravity drop hammer were also compared.

• Keywords: sabijanje; valjčić; deformacija; tvrdoća; simulacija
• Keywords (english): compression; cylinder; deformation; hardness; simulation
• Language: croatian
• URN:NBN: urn:nbn:hr:235:558114
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechatronics and Robotics, Autonomous Systems; Course: Production 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: 2022-07-06 11:56:17