Co2 molds (carbon dioxide moulding), Other Engineering

CO2 Molds (Carbon dioxide Moulding) is the process of hardening the moulds and cores by using carbon dioxide and sodium silicate liquid base binder is one of the most widely used process in foundry. In this process clean dry silica is thoroughly mixed with 3.5 to 5% sodium silicate liquid base binder in a mixer. The sand is then backed in the flask or the core box by standard moulding machines, core blowers or by hand. Sometimes other ingredients such as coal dust, pitch, etc. are added to improve collapsibility and such other properties.

          When the mould is packed properly CO2 gas is forced in the mould or the core at a pressure of about 15 N/cm2. The chemical reaction that takes place is

                       Na2OSiO3l.H2O+CO2 → Na2Co3 +SiO2.H­2O

                              Sodium         Carbon             Sodium        Silica gel

                              Silicate          dioxide             carbonate

         The silica gel is formed and this harden the sand and acts as a cement to bind the sand grains together.

         As shown in figure shows various steps followed in preparing the mould. The mould is prepared in the usual manner and CO2 gas is passed through the mould. The gassing is carried out by a probe having a number of holes at the bottom.

        The success of this process depends upon the method of introducing the gas which should be simple, rapid and uniform throughout the body of the sand.

        Following are the advantages of this process :

        (i) The operation is rapid and expensive core baking equipment is not required.

       (ii) The process can be mechanized and adopted for mass production.

 Semiskilled labor can be employed.

       (iii) Cores can be stored for a long period.

       (iv) Same sand can be used for both moulds and cores.

       (v) Handling of moulds is reduced.            

       (vi) Good surface finish and accuracy can be obtained.

       This process can be used for both ferrous and non-ferrous castings. The sand used in this process cannot be reclaimed. If sand with a silica base binder is kept for a long time it hardens in air. This is the major disadvantage of the process.

Posted Date: 8/3/2012 2:13:29 AM | Location : United States







Related Discussions:- Co2 molds (carbon dioxide moulding), Assignment Help, Ask Question on Co2 molds (carbon dioxide moulding), Get Answer, Expert's Help, Co2 molds (carbon dioxide moulding) Discussions

Write discussion on Co2 molds (carbon dioxide moulding)
Your posts are moderated
Related Questions
why germanium become intrinsic at high temperature

Electronics Engineering Assignment# Solve problems using DC electrical principles 1.3 A 220 F capacitor is required to store 11mJ of energy. What voltage needs to appear

The centre of pressure (CP) is defined as the point about which the resultant moment is zero; the net effect of the flow in terms of forces and moments would be the same as if the

Students are to undertake a tunnel blast design for the following conditions: • Tunnel is 5.5m wide by 5.5.m high • Rock is a granite with a UCS of 300 MPa • Drill hole diameter is


what is the consideration of time importance in financial management? how can time time be adjust illustrate you?

Bay cooling in Aircraft: There are two methods of bay cooling, they are: • Ram air cooling • Fan air cooling RAM AIR COOLING For ram air cooling, the aircraft has to

Let C(K) denote a European vanilla Call option with strike price K. Assume that all options are identical except for strike price, and strike prices satisfy (K1) What are the no-

THE IDEAL OPERATIONAL AMPLIFIER Although the characteristics of an ideal operational amplifier are unattainable, modern integrated circuit types can provide an extremely close

i have a coursework for finite element analysis of marine structure and i need help to solve it