Porosity may be the most persistent and common complaint of casting users. Forgings, machined parts and fabrications are

able to avoid porosity with ingot cast feedstock, mechanical processing and automated inspection of simple shapes. Porosity

in castings contributes directly to customer concerns about reliability and quality. Controlling porosity depends on

understanding its sources and causes. Significant improvements in product quality, component performance, and design

reliability can be achieved if porosity in castings can be controlled or eliminated.

Porosity in castings is due to bubbles being trapped during solidification. Porosity sources include entrapped air during

filling, centerline shrinkage that occurs during the final solidification, blowholes from unvented cores, reactions at the mold

wall, dissolved gases from melting and dross or slag containing gas porosity.

This paper is an update to a presentation to the 1980 AFS Casting Congress concerning gas holes in castings.(1) This update

will seek to review that work and try to articulate a framework for understanding and controlling porosity in castings. A

paper from the 1980 AFS presentation was published in 1981.

http://www.rastgar.com/wheel-hubs/document/Porosity%20in%20Castings.pdf

Porosity may be the most persistent and common complaint of casting users. Forgings, machined parts and fabrications are

able to avoid porosity with ingot cast feedstock, mechanical processing and automated inspection of simple shapes. Porosity

in castings contributes directly to customer concerns about reliability and quality. Controlling porosity depends on

understanding its sources and causes. Significant improvements in product quality, component performance, and design

reliability can be achieved if porosity in castings can be controlled or eliminated.

Porosity in castings is due to bubbles being trapped during solidification. Porosity sources include entrapped air during

filling, centerline shrinkage that occurs during the final solidification, blowholes from unvented cores, reactions at the mold

wall, dissolved gases from melting and dross or slag containing gas porosity.

This paper is an update to a presentation to the 1980 AFS Casting Congress concerning gas holes in castings.(1) This update

will seek to review that work and try to articulate a framework for understanding and controlling porosity in castings. A

paper from the 1980 AFS presentation was published in 1981.

http://www.rastgar.com/wheel-hubs/document/Porosity%20in%20Castings.pdf