Casting Concepts

10+Casting Defects and Causes observed during and after the Casting Process-Production|GATE

10+Casting Defects and Causes observed during and after the Casting Process:Casting is a process in which molten metal is to be poured into the moulding cavity and it is allowed for solidification and after solidification,the casting component was taken out by removing the mould called as Casting Process.While doing Casting of any component,every Engineer must know about the casting defects and causes that can occur during the casting process in a detailed way so that there can be minimum defects or no defects observed during casting process.Therefore in this article,I will be explaining about the 10+casting defects and causes observed during and after the Casting Process which are Blow holes,Scar,Blister, in a detailed manner.

10+Casting Defects observed during and after the Casting Process-Production|GATE
10+casting defects and causes observed during and after the Casting Process-Production|GATE

 

10+casting defects and causes observed during and after the Casting Process:

1.Blow holes (or) blow:

  • Low porosity property of moulding sand.
  • Allowing partial flow of molten metal in the gating system.
  • Aspiration effect present in the gating system.
blow holes in casting process
blow holes in casting process

2.Scar:

The air or gas bubble present on the surface of casting is called scar.

3.Blister:

Air or gas bubble present near to the surface of casting but not imposed to open atmosphere.

4.Porosity:

Small sized air or gas particles inside the casting is called porosity.

porosity in casting process
porosity in casting process

5.Dross:

  • The impurities or the foreign particles present inside the casting is called dross.
  • This is due to improper separation of impurities present in the molten metal.
  • This can be eliminated by using strainer, by providing skimbob and by offsetting axis of runner and ingate.

6.Inclusion (or) sand inclusion:

  • Sand particles present inside the casting is called as casting or sand inclusion.
  • It is because of sand erosion taking place during casting.
Inclusion in casting process
Inclusion in casting process
  • This is due to turbulent flow of molten metal in the gating system.
  • Using gating system for filling the cavities in loose sand moulds.
  • Use the top gating system for filling the cavities having the height >200mm.

7.Shinkage cavity (or)void:

  • The open space produced in the casting due to non-availability of molten metal for compensating liquid shrinkages during solidification.
  • It can be eliminated by providing chills.
shrinkage in casting
shrinkage in casting

8.Misrun:

Non-filling of projected or extended portion of casting cavity or by increasing degree of superheat of moltenmetal.

Misrun in casting process-Casting defects
Misrun in casting process-casting defects and causes

9.Rat tail:

  • The tail like elements produced in the surface of casting is called rat tail defect.
  • This is produced because of usage of wax pattern with green sand mould.

10.Shift:

  • A mismatch between cavities of cope of drag produces shift (or) step in the casting called as shift defect.
  • To avoid this dowel pins are used.
shift or mismatch in casting process-casting defects
shift or mismatch in casting process-casting defects and causes

11.Cold shut:

  • Discontinuity present in the casting cavity due to hindering contraction (shrinkage) is called as cold shut.
  • It is mainly produced in step-gating system.
  • It can be eliminated by increasing the degree of superheat.
coldshut in casting process-shift or mismatch in casting process-casting defects
coldshut in casting process-shift or mismatch in casting process-casting defects and causes

This is the complete explanation of 10+casting defects and causes observed during and after the Casting Process.If you have any doubts feel free to ask from the comments section.

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