magistrsko delo
Aleš Menegatti (Avtor), Primož Mrvar (Mentor), Sebastjan Kastelic (Komentor)

Povzetek

Magistrsko delo je bilo izvedeno z namenom zmanjšanja penetracije taline na dveh ulitkih z oznako 358 in 088 iz sive litine z lamelnim grafitom. Napaka penetracije se je ponavljala na istih delih pri obeh ulivnih sistemih in je bila posledica previsoke temperature litja, prehitrega strujanja taline skozi formo in tlaka pri zadnji zapolnitvi livne votline. Najprej smo v programu ProCast izračunali livarske procese v obeh ulivnih sistemih. V programu smo pripravili ustrezno geometrijo z mreženjem, koeficiente prestopa toplote med volumni in opredelili materialne lastnosti ter robne pogoje. Kot rezultat smo dobili simulacije strujanja taline, tlaka v formi, temperaturnega polja, erozije forme in strjevanja ulitka. Iz simulacij smo ugotovili, da na mestu nastanka penetracije taline prihaja do povečane temperaturne obremenitve peščene mešanice, hitrejšega strujanja taline, erozije forme in povišanega tlaka ob zapolnitvi, ki je posledica zadnjega mesta polnjenja livne votline. V sklopu magistrskega dela smo v laboratoriju izvedli test vpliva parametrov na peščeno mešanico, kjer smo spremljali penetracijo taline in posledično reakcijo peska na ulitek. Pri eksperimentu smo spreminjali togost in vlažnost peščene mešanice ter segrevanje površine livne votline. Po analizi ulitkov smo ugotovili, da na penetracijo najbolj vpliva vlažnost peščene mešanice. S spreminjanjem časa litja in temperature litja smo v simulaciji znatno zmanjšali napako penetracije pri obeh ulivnih sistemih. Za ulivni sistem z oznako 358 smo dodatno optimizirali elemente ulivno napajalnega sistema, da smo enakomerno razporedili dovajanje taline in s tem zmanjšali toplotno obremenitev peščene mešanice .

Ključne besede

bentonitna peščena mešanica;siva litina z lamelnim grafitom;penetracija;hitrost strujanja taline;forma.;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UL NTF - Naravoslovnotehniška fakulteta
Založnik: [A. Menegatti]
UDK: 669
COBISS: 186271235 Povezava se bo odprla v novem oknu
Št. ogledov: 70
Št. prenosov: 7
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: penetration and reaction between bentonite sand mixture and flake graphite cast iron
Sekundarni povzetek: The master’s thesis was carried out to reduce and eliminate the penetration defect in two castings with codes 358 and 088 of grey cast iron castings with lamellar graphite. The penetration defect repeatedly occurred in the same parts of both casting systems and was caused by high casting temperature, the velocity of molten metal through the mold, and pressure at the final filling of the casting cavity. First, we calculated the casting processes in both casting systems in the ProCast program. In the program, we prepared the appropriate geometry with meshing, heat transfer coefficients between volumes, and defined material properties and boundary conditions. As a result, we obtained simulations of molten metal velocity, pressure in the mold, temperature field, erosion of the mold, and solidification of the alloy. From the simulations, we concluded that at the location of the penetration defect, thermal load on the sand mixture, the faster velocity of molten metal, and erosion of the mold was increased. Pressure upon filling, which is a consequence of the last filling place of the casting cavity, was also increased. As part of the master’s thesis, we conducted a test in the laboratory on the influence of parameters on the sand mixture where we monitored the penetration of molten metal and consequently the reaction of sand to the casting. During the experiment, we varied the stiffness and moisture of the sand mixture and heated the surface of the casting cavity. After analyzing the castings, we found that the moisture of the sand mixture influences penetration the most. By changing the pouring time and casting temperature, we significantly reduced the penetration defect in both casting systems in the simulation. For the casting with code 358, we additionally optimized the elements of the casting-feeding system to reduce the velocity of the molten metal.
Sekundarne ključne besede: bentonite greensand mixture;flake graphite cast iron;penetration;fluid velocity;mold.;
Vrsta dela (COBISS): Magistrsko delo/naloga
Študijski program: 0
Konec prepovedi (OpenAIRE): 1970-01-01
Komentar na gradivo: Univ. v Ljubljani, Naravoslovnotehniška fak., Oddelek za materiale in metalurgijo
Strani: XVIII, 53 str.
ID: 22918678