Title

POROSITY IN CYLINDER HEAD CASTING OF ALUMINIUM

POROSITY IN CYLINDER HEAD CASTING OF ALUMINIUM

Authorship

Santos, João Bosco dos; Teixeira, Ricardo Luiz Perez

Santos, João Bosco dos

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Teixeira, Ricardo Luiz Perez

13 Articles, Downloaded 11681 Times

DOI

10.5151/2594-5327-23210

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Abstract

The porosity in cast aluminum automotive components can compromise the quality of the casting during assembly of the internal combustion engine. The concentration of the porosity in large quantities can cause problems communicability between walls melt causing leaks like for example mixing oil and water the mechanical component in service. Porosities very near the surface of the machined head engine, below the joint seal, can cause leakage in the coupling cast components. The casting must provide a component with high internal health, free of voids and / or cavities in the melt, but the mechanism of formation porosity is associated with problems inherent in the process of the gravity casting alloys. The Presence of iron oxides and intermetallic phases, no cleaning bath and a favorable environment for the incorporation of gas in the liquid metal to be considered to the formation of porosity in the molten aluminum metal during solidification. In this paper, reported to clean the alloy liquid with salt pans in preheated during the degassing with nitrogen gas (N2), since this salt is used to keep the liquid bath protected from contact with moisture in the air, the main source of hydrogen gas (H2).The cylinder head motor aluminum was chosen for the study because it has thin walls with internal cavities narrow and is powered by a homogeneous volume of liquid material (feeder) which in this case has a regular geometric shape and mass. Every section of the cylinder head just below the feeder was the area selected for analysis because of this proximity to the hot melt supply and therefore prone to the appearance of porosity. The results of the experiment to reduce the porosity due to hydrogen gas using cleaning liquid alloy with salt protective preheated were significant. Since no limitation of the gravity casting process to obtain a mechanical component blown free of porosity is suggested that the functionality of this component in service will be better evaluated in the initial phase of definition of the design data for execution of the melt. Still, whichever choice of merging this component of the engine by gravity casting process, eligibility criteria should be established during the development stage of the project for the manufacture of automotive components.

The porosity in cast aluminum automotive components can compromise the quality of the casting during assembly of the internal combustion engine. The concentration of the porosity in large quantities can cause problems communicability between walls melt causing leaks like for example mixing oil and water the mechanical component in service. Porosities very near the surface of the machined head engine, below the joint seal, can cause leakage in the coupling cast components. The casting must provide a component with high internal health, free of voids and / or cavities in the melt, but the mechanism of formation porosity is associated with problems inherent in the process of the gravity casting alloys. The Presence of iron oxides and intermetallic phases, no cleaning bath and a favorable environment for the incorporation of gas in the liquid metal to be considered to the formation of porosity in the molten aluminum metal during solidification. In this paper, reported to clean the alloy liquid with salt pans in preheated during the degassing with nitrogen gas (N2), since this salt is used to keep the liquid bath protected from contact with moisture in the air, the main source of hydrogen gas (H2).The cylinder head motor aluminum was chosen for the study because it has thin walls with internal cavities narrow and is powered by a homogeneous volume of liquid material (feeder) which in this case has a regular geometric shape and mass. Every section of the cylinder head just below the feeder was the area selected for analysis because of this proximity to the hot melt supply and therefore prone to the appearance of porosity. The results of the experiment to reduce the porosity due to hydrogen gas using cleaning liquid alloy with salt protective preheated were significant. Since no limitation of the gravity casting process to obtain a mechanical component blown free of porosity is suggested that the functionality of this component in service will be better evaluated in the initial phase of definition of the design data for execution of the melt. Still, whichever choice of merging this component of the engine by gravity casting process, eligibility criteria should be established during the development stage of the project for the manufacture of automotive components.

Keywords

Porosity; Cylinder head; Clean alloy; Casting; Aluminum alloy; Flux salt; Degassing.

Porosity; Cylinder head; Clean alloy; Casting; Aluminum alloy; Flux salt; Degassing.