Deformation and wear in a H21 (3Cr2W8V) steel die during hot forging: simulation, mechanical properties, and microstructural evolution

Abstract

Deformation and wear in a hot-forging die made of H21 steel was investigated using finite element analysis, nanoindentation, microhardness, optical scanning method, electron backscattering diffraction, and transmission electron microscopy. The results showed that deformation and wear were concentrated more in some die regions during the hot-forging process. In these regions, the processing parameters such as strain, strain rate, and temperature were suitable for the occurrence of different softening mechanisms such as the formation of blocky ferrite phase, recovery of dislocations, tempering, and dynamic recrystallization. In addition, dynamic recrystallization happened by both the continuous and discontinuous mechanisms causing the formation of fine and equiaxed grain with a low density of dislocations. These softening mechanisms reduced nano hardness values from 6.69 GPa in base material to 3.91 GPa in deformed regions. The results of this study may help scientists and engineers understand the origin of the failure of hot-forging dies for industrial applications.

Keywords

• Optical scanning method
• Wear
• Nanoindentation
• Electron backscattering diffraction
• Dynamic recrystallization