Chvorinov''s rule, Other Engineering

Q. Why is it desirable to design a casting to have directional solidification sweeping from the extremities of the mould to riser based on Chvorinov's rule? What would be an ideal shape for a riser? Discuss a desirable shape from a practical perspective.

Ans. The optimum riser diameter for a given casting can be opened by a Chvorinov's Rule :

         Chvorinov's Rule : It states that the freezing time of a casting.

                            1   (V)2

                      t =  q2 (A)

 

q = solidification constant, depending on the composition of cast metal and the positioning of the mould cavity, like, along a vertical or a horizontal axis.

          V   = ratio of volume of the casting to its surface area.

          A 

         Values of (V)2 and freezing time have been found out by actual

                       (A) 

experiments for different metals and alloys and for different cylinder diameters.

Best riser is one whose (V)2 is 10% to 15 larger than that of the casting.

                                (A)

Riser Design : If no riser is provided during casting, the solidification will start from walls and liquid metal in the centre will be surrounded by a solidified shell and the contracting liquid will produced voids towards the centre of the casting. Further cooling of the solid in centre sets up undersirable stresses in the casting.

        Provision of risers overcomes these problems as these supply molten metal for a solidifying casting. For this purpose, the risers must be large enough to remain liquid after the casting has solidified and must contain sufficient metal to provide for the contraction losses. Further these should be so positioned that they continue to supply metal throughout the solidification period.

Posted Date: 8/3/2012 6:33:17 AM | Location : United States







Related Discussions:- Chvorinov''s rule, Assignment Help, Ask Question on Chvorinov''s rule, Get Answer, Expert's Help, Chvorinov''s rule Discussions

Write discussion on Chvorinov''s rule
Your posts are moderated
Related Questions
Turbine Blade Clearance. Creep is term used to describe the continuous and permanent stretching of turbine blades due to high temperatures and centrifugal forces acting on the

copper and its alloys

Q.   What is crystal imperfection? Briefly discuss all types of point defects in crystals. Ans. The various type of crystal imperfection are as follows: (1)   Point de


Nomenclature • Information source device producing information to be communicated • Binary digit (bit) fundamental information unit for all digital systems; unit of informat

AIRCRAFT INTERNAL AND EXTERNAL MARKINGS SMOKING IN AIRCRAFT - Reference: ANO Article 66 and JAR-25.791 Every aircraft registered in the U.K. must have a notice indicati

Ask queelectron - proton hypothesis

advantages and disadvantages of cold and hot working

Presintering is an operation in which the powder metallurgy components after compaction are heated for a short time to a temperature considerably below the final sintering tempera

Q. Explain the grain growth. Ans. Grain growth: After Recrystallization is complete, the strain free grains will continue to grow if the metal specimen is left at elevated te