Casting is a process in which the molten metal is poured into the casting cavity and it is allowed for solidification. After solidification, take the casting out by breaking the mold, called a casting process. In this article, I am going to discuss on Types of Casting Allowances and Types of Casting defects.
The different types of allowances observed during and after the casting process and are as follows.
There are five types of casting allowances are there, and those are:
The explanation of the above types of allowances is as follows...
During cooling of the material in the Casting process, in all the three stages, the material is getting shrinking(reducing its dimensions or volume). But, shrinkage allowance taking place in 1st two stages is called Liquid Shrinkage.
The extra dimension provided on the casting and it will be removed by machining after the casting has been completed is called Machining Allowance.
Making the vertical surfaces of the pattern into inclined surfaces is called Draft Allowance.
To maintain the required size of the casting, the original size of the pattern has to be reduced by an amount called Shake Allowance.
To get the vertical legs of U shaped[Distortion Allowance complete]. the original pattern has to be bend inverse so that during solidification, the legs are bending outwards and becoming vertical legs.
The amount by which the legs are bending Inverse is called as Distortion or Bending allowance. This is the complete explanation of all types of allowances in a detailed manner.
Now let's discuss the crucial steps involved in Casting Process.
Metal Casting Process: Metal Casting process is a process in which the liquid molten metal is poured into the casting cavity, whose shape is same as that of the shape of the casting to be produced, allowing to solidify and after solidification, the casting will be taken out by breaking the mold and is called as Metal Casting process.
There are several types of casting defects can be obtained while casting, here I mentioned 11 most important casting defects.
The air or gas bubble present on the surface of the casting is called a scar.
Air or gas bubble present near to the surface of casting but not imposed to open atmosphere.
Small-sized air or gas particles inside the casting is called porosity.
Non-filling of projected or extended portion of the casting cavity or by an increasing degree of superheat of molten metal.
This is the complete explanation of Casting Allowances and Casting defects. If you have any doubts feel free to ask from the comments section.