Liquid hot isostatic pressing process to improve properties of thixoformed parts

摘要

Already introduced many years ago as a concept, the hat isostatic pressing process has been widely and successfully used for niche and high-performance-demanding markets such as aerospace and car racing. The main reason why this bright idea of post-processing shaped materials, mainly castings, never became an industrial process for larger markets like the automotive is cost. The means used up to now to apply high pressure on the component to be treated in a vessel at high temperature, where the material softens and compacts uniformly, is a gas.This leads to long treatment time and cost issue, added to the highly risky plants where the vessel containing the parts during the treatment is working under heavy stress conditions (pressure can reach 1300 atmospheres when aluminum is treated.Recently MCT- USA and Teksid-Italy developed and industrialized, in partnership with Idra-Italy a new hat isostatic pressing process, called Liquid HIP (LHIP), where the mean used to apply the pressure to the components to be treated is a liquid salt. The process can be considered a technology breakthrough. Its cost competitiveness will open a bright future in the next few years far HIP applied to aluminum automotive components for mass production, with the goal of having higher properties on treated parts and reduced scrap level in the casting process chain.This paper describe the effect of LHIP on thixo formed castings.