Abstract
Hot isostatic pressing (HIP) allows the production of complex components geometry. Generally, a high quality of the components is achieved due to the well managed composition of the metal powder and the non-isotropic properties. If a duplex stainless steel is produced, a heat treatment after the HIP-process is necessary to remove precipitations like carbides, nitrides and intermetallic phases. In a new process, the sintering step should be combined with the heat-treatment. In this case a high cooling rate is necessary to avoid precipitations in duplex stainless steels.
In this work, the influence of the HIP-temperature and the wall thickness on corrosion resistance, microstructure and impact strength were investigated. The results should help to optimize the process parameters like temperature and cooling rate.
For the investigation, two HIP-temperatures were tested in a classical HIP-process step with a defined cooling rate. An additional heat treatment was not conducted. The specimens were cut from different sectors of the HIP-block. For investigation of the corrosion resistance, the critical pitting temperature was determined with electrochemical method according to EN ISO 17864.7 An impact test was used to determine the impact transition temperature. 8 Metallographic investigations show the microstructure in the different sectors of the HIP-block.
