Abstract
For establishing an optimum HIP condition to obtain high productivity, changes in density and bending strength were studied relating to various HIP conditions.
The results were summarized as follows :
1) The combination of 1100°C, 400 kg/cm2, and 30 minutes is enough for obtaining the theoretical density, and that of 1200°C, 400 kg/cm2, and 30 minutes is enough for reaching a saturation in bending strength.
2) The bending strength can be approximately expressed as a function of only the density.
3) The pressure plays a fundamental part of densification caused by plastic and creep deformation especially at the lower density region. The temperature is important for increasing diffusion to densify and to improve strength, especially near the theoretical density region, as well as for assisting the role of pressure by decreasing deformation resistance. The holding time is instrumental in the progress of creep and in the completion of sintering.
