Reinforcement of rice husk in ceramic shell mould system for investment casting process

Kamarudin, Noor Hasliza (2012) Reinforcement of rice husk in ceramic shell mould system for investment casting process. Masters thesis, Universiti Tun Hussein Onn Malaysia.

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Abstract

Generally, production of metal component via investment casting process need a development of a very thin ceramic shell mould that can withstand a higher molten metal temperature. Development of ceramic shell mould is very crucial as its involves several times of dipping process followed by the drying and firing stages. Typically, this ceramic shell mould is very brittle and easily prone to cracks that will lead to the casting defects and handling problem at early stage. Therefore, this work focuses on the development of brittle ceramic shell mould via reinforcement method. Rice husk fibers and rice husk ash were selected as a reinforcement material due to the facts that its contains higher percentage of silica. The samples were prepared by three compositions which are untreated rice husk fiber, rice husk treated fiber by sodium hydroxide and rice husk ash. The mechanical and physical properties of ceramic shell mould layering system were measured via Modulus of Rupture, density and porosity, permeability, shrinkage, thermal expansion and observation of metal casting. Experimental results show that the reinforced ceramic shell mould with treated rice husk fiber achieved highest green strength (1.34 MPa). However, ceramic shell mould with rice husk ash shows the highest fired strength (4.87 MPa). Indeed, rice husk fibers additions have greatly increased porosity after firing at 1000 ºC by values of 20.06 % and hence promotes increments of permeability by value of 2.46 x 10-11 cm2. The present of silica also gives highest density, lowest shrinkage and thermal expansion by value of 1.9516 g/cm3, 0.1258 mm and 0.088 % respectively for ceramic shell with rice husk ash. Observation of metal casting shows that reinforced ceramic shell can withstand high molten metal temperature without cracking. Hence, reinforced ceramic shell has reduced production time and cost via avoiding failure to the mould and end cast product.

Item Type:Thesis (Masters)
Subjects:T Technology > TA Engineering (General). Civil engineering (General) > TA630-695 Structural engineering (General)
ID Code:3712
Deposited By:Normajihan Abd. Rahman
Deposited On:20 Jun 2016 10:42
Last Modified:20 Jun 2016 10:42

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