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
Thermoelectric effect The measurement of temperature using a thermocouple relies on Seebeck effect. The electrons occupy different energy levels in different materials

explain the design should be traceable to the analysis model

R-134a is compressed in an adiabatic compressor from saturated vapor at 100kPa to a final state at 1 MPa and 50 degrees Celcius. Before entering the compressor, the R-134a receive

Q.  With necessary theory explain the formation of spectrum by a plane transmission grating when composite light falls on it OR How does plane diffraction grating for

AAA has 1,000,000 shares of common stock trading at $20.00 per share. The company''s debt consists of 2,000 $1,000 par value 10-year 7.0% annual coupon bonds with semiannual paymen


Derive the functional relationship between the no-arbitrage values of the two vertical spreads.

based on your managemet style or your personal perspective, discuss how you developed your viewpoint how it will influence the way you manage, and what challenges you migt face if

how would I find assistance with such toics as: probability assessment methods, risk modeling, stochatic dominance and multi-attribute methods?

JFET OPERATION Figure shows the operation of a JFET. The JUGFET has a physical structure that can be represented by the diagram shown in Figure. In Figure, if the N-Ty