Effect of Hot Isostatic Pressing on the Microstructure of K417G Cast Turbine Discs

Abstract

The present study focused on the effect of hot isostatic pressing (HIP) treatment on the microstructure of K417G superalloy. The experimental results showed that after the HIP treatment the size and volume fraction of the porosities significantly decreased. In addition, the dendritic structure and γ/γ' eutectics in the as-cast specimens became obscure after the HIP treatment due to the improvement of segregation. The γ′ phases in the dendrite core were smaller than those in the interdendritic region, whether in the as-cast or HIP specimens. The slow cooling at the end of the HIP treatment leads to the irregular morphology of the γ′ phases.

Rheological Properties and Microstructure of PH1 Stainless Steel Produced by Selective Laser Melting

“…In order to eliminate the anisotropy and to reduce porosity, the following post-processing methods of SLM parts have been developed and investigated: heat treatment [7,10], hot isostatic pressing (HIP) [10,11], technology of additive manufacturing including rolling each built-up layer by a roller [12][13][14] and others. HIP allows removing bulk defects, porosity, residual stresses which are typical for as-built SLM-produced PH1 stainless steel [10,11]. However, HIP is very expensive process due to high equipment cost, besides it's necessary to note limitations related to dimensions of the parts.…”