Search Results for aluminum castings

Porosity in aluminum is caused by the precipitation of hydrogen from liquid solution or by shrinkage during solidification, and more usually by a combination of these effects. Nonmetallic inclusions entrained before solidification influence porosity formation and mechanical properties. This chapter describes the causes and control of porosity and inclusions in aluminum castings as well as the combined effects of hydrogen, shrinkage, and inclusions on the properties of aluminum alloys. In addition, it discusses the applications of radiography to reveal internal discontinuities in aluminum.

The metallurgy of aluminum and its alloys offers a range of opportunities for employing heat treatments to obtain desirable combinations of mechanical and physical properties such that castings meet defined temper requirements. This chapter discusses the processes involved in solution heat treatment, quenching, precipitation hardening, and annealing of aluminum alloys. The effects of these processes on dimensional stability and residual stresses are also discussed. Troubleshooting and diagnosis of heat treating problems are covered in the concluding section of the chapter.

This chapter reviews and provides data tables for the wide range of properties and performance characteristics that are possible with specific aluminum casting alloys and tempers. Properties and performance attributes addressed include casting and finishing characteristics; typical physical properties; typical and minimum (design) mechanical properties; fatigue strength; fracture resistance, including subcritical crack growth; and resistance to general corrosion and to stress-corrosion cracking. The chapter concludes with information on the properties of cast aluminum matrix composites.

Aluminum casting alloy compositions parallel those of wrought alloys in many respects. However, because work hardening plays no significant role in the development of casting properties, the use and purposes of some alloying elements differ in casting alloys versus wrought alloys. This chapter provides information on specifications and widely used designation systems and alloy nomenclature for aluminum casting alloys. It describes the composition of seven basic families of aluminum casting alloys: aluminum-copper, aluminum-silicon-copper, aluminum-silicon, aluminum-silicon-magnesium, aluminum-magnesium, aluminum-zinc-magnesium, and aluminum-tin. The chapter discusses the effects of alloying elements on the properties of cast aluminum. It provides information on various alloys that are grouped with respect to their applications or major performance characteristics.

This chapter begins with information on the historical development of aluminum alloy castings. It then covers the basic factors involved in the selection of a casting process. This is followed by sections describing the various categories of casting processes and their variants: expendable mold gravity-feed casting, nonexpendable (permanent) mold gravity feed casting, and pressure die casting. Next, the chapter describes the technologies used to produce premium engineered castings and when such castings may be relevant. The chapter concludes with descriptions of other process technologies used with castings, including metallurgical bonding, metal-matrix composites, and hot isostatic pressing.

Casting is one of the most economical manufacturing processes for providing shape to components of machinery and is used in a wide range of industries. This chapter is a brief account of the advantages, applications, limitations, and market growth of aluminum casting. It also provides information on the process of conversion of steel and iron parts to aluminum.

This appendix tabulates chemical composition limits for commonly used aluminum casting alloys registered with the Aluminum Association (AA).

This appendix includes composition limit data for aluminum castings and ingots.