HIPing: A potent post casting treatment for high integrity aluminium castings

Abstract

The increasing use of high integrity Al castings for repeated loading applications warrants improved fatigue properties as well. The principal cause for the lower fatigue properties and reliability of aluminium castings is the presence of defects and inhomogenities, which are the preferred fatigue initiation sites. Hot Isostatic Pressing (HIPing) is a powerful post casting treatment for eliminating defects like shrinkage porosity and hydrogen pinholes leading to densification and enhanced mechanical properties of the castings meant for high performance applications. This paper brings out the current status of this potent post casting treatment for high integrity castings including basic of HIPing, its variants and their pros and cons and its effects on both microstructure and mechanical properties of aluminium alloy castings.