Influence of thixoforming on structure development of the tool steel

Abstract

Forming in the thixotropic state is one of the alte rnative forming methods, which allows producing semi-products with relatively complicated shape. Th e process is based on semi-product forming in the region between solid and liquid, where the material exhibits the thixotropic behaviour. This technology applies especially to higher-alloyed ste els, which are otherwise processed by pressure casting. Thixoforming runs in the die cavity. Among the advantages of this technology belongs the possibility to produce components with complicated shape in one step and to utilize lower forming forces. On the other hand, high forming temperature s and the narrow forming temperature interval can be considered as disadvantages. To reach the th ixotropic behaviour necessary for obtaining the required component shape, the parameters of semi-so lid state play an important role. These include, for example, the fraction of the liquid phase, the shape of solid particles and the location of the li quid phase in the structure. The tool steel was used for the development of an alternative forming process. The structures were observed using light and laser confocal microscopy. The fraction of liquid phase and the size of solid particles were evaluated via image analysis.