Gray Cast Iron Casting Cooling
Gray Cast Iron Casting Cooling
(OP)
I am a Lean Manfacturing Engineer hence my knowledge in metallurgy is limited (though my fascination for this field has lead to try and learn);.....a major bottleneck in my process is the cooling time (static air-8 hrs) after the component (gray cast iron) is cast.
At what temperature can I force air / water quench a gray cast iron casting without changing material properties + machinability?
Thanks for all the help.
mechvhstech
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Mech Rulz





RE: Gray Cast Iron Casting Cooling
RE: Gray Cast Iron Casting Cooling
RE: Gray Cast Iron Casting Cooling
Some of them are large thin walled castings (48" X 31" X 8") though there are a few variations. The CI grade is 25 and they are shaken out (some sand always exists therefore after cooling there is shot blast operation).
As mentioned they are shaken out and transported to a cooling warehouse. There is a concern with distortion although there is a fair amount of machining tolerance. hard spots will probably affect machining.....but will depend on the no. of hard spots in the matrix.
Thanks.
mechvhstech
=========================================
Mech Rulz
RE: Gray Cast Iron Casting Cooling
Once the castings have solidified and are well below the freezing range possibility of hard spots due to white iron formation does not exist.
You can start using forced air cooling with a thin mist of water once the castings are below 400C. Ofcourse the whole place will be messy and humid. how will you handle this situation.
You may progressively increase the temperature of hot shakeout for rapid cooling as you gain experience. Motor body castings were given a hot shakeout at 750-800 C and then stir air cooled.Higher temperature shakeout would often lead to an epidemic of fin breakage.
RE: Gray Cast Iron Casting Cooling
I had a cooling tunnel with a forced air + mist cooling system.
This is similar to the one I have seen with a conveyor mode.
Are you familiar with such as system?
Thank you for all your answers.
-mechvhs
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Mech Rulz
RE: Gray Cast Iron Casting Cooling
You will probably have to experiment with your casting and determine the appropriate cooling rate as casting cross section variation and surface to mass conditions will affect the ability to cool a casting. There could be other considerations from the machining perspective the cooling could impact the machinability of the iron and the residual stresses in the casting could cause tolerance problems if the part is machined to a tight tolerance.
I hope you are shot blasting after the cooling process not before as the parts will flash rust with the water spray.