Lijevanje impelera pumpe od nehrđajućeg čelika

master's thesis

• Title (english): Casting stainless steel pump impeller
• Author: Mateo Bratić
• Mentor: Branko Bauer (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 ovome radu analiziran je lijevani impeler pumpe od nehrđajućeg čelika koji je imao greške nakon lijevanja.
U prvom dijelu dan je pregled nehrđajućih čelika, podjela i karakteristike svake od skupina. Nakon toga su navedeni postupci lijevanja te pobliže razrađeni postupci koji su korišteni tijekom ovog rada.
U eksperimentalnom dijelu prvo je analiziran postojeći odljevak. Analiza kemijskog sastava i karakterizacija mikrostrukture pokazala je da se radi o austenitnom nehrđajućem čeliku AISI 316L. Nakon toga je konstruiran CAD model postojećeg odljevka i njegovi sustavi ulijevanja i napajanja. Postojeći odljevak lijevan je u pješčani lijev s ručnim kalupljenjem te ima semitlačni uljevni sustav. Izvršena je simulacija postupka lijevanja u simulacijskom programu ProCAST.
Analiza rezultata pokazala je da greška na odljevku nastaje u dijelu velike debljine stijenke zbog nedovoljno dobrog napajanja talinom tijekom skrućivanja.
Usporedbom rezultata simulacije i postojećeg odljevka zaključeno je da su u oba dva slučaja iste greške nastale u istom području odljevka te se time potvrđuje valjanost rezultata simulacije.
Kao prijedlog poboljšanja postupka lijevanja, postavljeno je hladilo na odljevak i konstruiran je tlačni uljevni sustav. Hladilo je trebalo osigurati usmjereno skrućivanje taline prema pojilu, a tlačni uljevni sustav pouzdano punjenje kalupne šupljine. Nakon provedbe simulacije u simulacijskom programu ProCAST i analize rezultata, odljevak je bio ispravan i bez greški.

Abstract (english)

Within this thesis, cast stainless steel impeller with porosity defects was analysed.
The first part gives overview of stainless steel and the division and characteristics of every group. After that, casting methods are listed with the methods that are used within this thesis explained in detail.
In the experimental work, an analysis of the casting was conducted at first. Study of chemical composition and microstructure characterization showed that material was austenitic stainless steel AISI 316L. After that, CAD model of existing casting was designed with belonging gating and feed systems. Existing casting was casted with manual sand casting in green sand and with pressurized gating system. Simulation of the process was conducted in simulation software program ProCAST.
Analysis of the simulation results showed that casting had defect in high thickness area because of insufficient feeding with melt during the solidification.
By comparing the results from simulation and from existing casting it was concluded that same defects appeared in the same area which verifies simulation results.
As an improvement proposal, chill was installed onto the casting and pressurized gating system was designed. Chill should have enabled directional solidification toward the riser and pressurized gating system should have enabled reliable fill of the mould cavity. After simulation in simulation software program ProCAST was conducted and results analysed, casting was correct and without defects.

• Keywords: nehrđajući čelik; simulacija; lijevanje; ProCAST
• Keywords (english): stainless steel; simulation; casting; ProCAST
• Language: croatian
• URN:NBN: urn:nbn:hr:235:882515
• 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: 2022-07-05 19:22:28