Sources of Porosity in Die Castings. The formation of bubbles in the castings results to die casting porosity. Porosity in die castings in defects caused by bubbles, often resulting from machine inefficiency, temperature variances, etc.

The following enumerates the most common sources of porosity in die castings.

Air Entrainment

Once air is trapped in the castings upon pouring of metallic substance into the die and the same air was not able to escape during solidification, a metal casting defect is expected to result from it. Both the temperature and the pressure directly affect the formation of such die casting porosity.

Blow Holes

When from a core, gas bubbles are blown into the liquefied metal, causing holes when solidified. This is also known as blisters.

Oxides

Some defects in die casting are caused by oxides. Oxide formation causes defects on the surface or in the subsurface of the die cast parts. In steel castings for example, the removal of inclusion material by blasting causes associated porosity. These are the grassy areas in steel castings.

Pinholes

Pinholes are characterized by the formation of tiny bubbles caused by less soluble gases. During solidification, soluble gases must dissolve upon combination with liquefied metal. Once insoluble gasses remain, defects such as pinholes will appear on the castings.

Shrinkage

Shrinkage normally occurs during solidification of liquid metal. An allowable degree of shrinkages is considered by die casting manufacturing companies. However when shrinkages goes beyond the allowable level forming a defective casting, this is considered a manufacturing cost. Die casting products are often deformed due to shrinkages in various forms.

This is the blog on the Kinetic Die Casting Company web site. KDC also writes about Porosity in Die Casting. Look at this website page for more details: www.kineticdiecasting.com/porosity.html. Contact Kinetic Die Casting Company at 818-982-9200 or email us at sales@kineticdc.com. Use this webpage to request “die casting part prices” www.kineticdiecasting.com/replyform.html