Abstract
The tensile strength of sintered iron is improved by steam treatment. Some experiments were conducted for explaining the effect.
Tensile tests were conducted on two kinds of different powders, reduced and electrolytic ones, to investigate the effects of tests on their properties. However, no effects were given by the tests.
On the other hand, the change in internal porosity was observed by microscopy.
These experiments and observations showed that the improvement in tensile strength would be due to the following three effects:
1) Effect of impregnation
2) Decrease in notch effect
3) Decrease in density of skeleton
A model of pores was prepared by determination of the rate of impregnation effect. The above three effects were explained by a schematic graph given by the model.
