INFLUENCE OF HEAT TREATMENT ON STRESS-DEFORMED STATE FOR MATERIALS OBTAINED BY POWDER INJECTION MOLDING

Abstract

It was found that the materials Catamold8740 and PolyPOM8740 after sintering have a pearlitic-ferritic structure with existing structural inhomogeneities and fine-crystalline foreign inclusions. The influence of heat treatment on the stress-strain state of low-alloy steels Catamold8740 and PolyPOM8740 was established by X-ray diffraction analysis methods and it was shown that macro stresses in materials decrease by an order of magnitude. The maximum macro stresses in powder mixtures during sintering reach s_macro ~ 1.4 GPa. After heat treatment, the residual macro stresses are significantly reduced and amount to s_macro ~ 150-200 MPa in both materials. The microstresses in the Catamold8740 material after heat treatment remain at the level of ~ 700-840MPa, and in the PolyPOM8740 the microstresses drop to almost zero (<60MPa).