Abstract
This investigation was undertaken to clarify the effects of pores on the mechanism of the impact fracture of sintered iron, and also on the absorbed energy. Specimens, 10×10×55 mm, were compacted from electro-lytic iron powder under the pressure of 2-9t/cm2 and sintered in hydrogen for 1 hr at 850°C. The bending load-deflection diagrams of U-notched specimens were obtained by an instrumented 30 kg⋅m-Charpy tester and by an Instron type universal testing machine.
Results were summariged as follows.
The necessary time for the impact fracture of sintered iron was too short to obtain the accurate impact load-deflection diagrams as in the case of cast iron. Therefore, the, slow bending diagrams were used for the analysis. The product of the strength and the ductility, both of which were expressed as respective functions of the density, was found to be in proportion to the slow bending energy. This fact was considered to be the reason why the notch effect-of pores on the impact value was stronger than those on the ultimate tensile strength and on the tensile elongation.
