Abstract
Effects of repressing and resintering on the physical and mechanical properties of sintered compacts were studied.
The results obtained were as follows :
(1) Microstructures of sintered compacts have a large effect on the repressing ratio and the increase in density. Ferritic and austenitic structures give large repressing ratios.
(2) On repressing sintered compacts containing Mn 10% and C 1.2% which might show martensitic structure, pre-sintering at a lower temperature and pre-pressing at a lower compacting pressure are recommended, while, for the compacts containing Mn 20% and C 2.0% which might show austenitic structure, pre-sintering at a higher temperature and prepressing at a higher compacting pressure are recommended.
(3) On cyclic sintering and pressing, tensile strength and elongation of sintered compacts of ferritic and austenitic structures are saturated by a single process of repressing and resintering, but those of martensitic structure are not saturated even by repressing and resintering three times. Repressing is less effective for martensitic structures than for ferritic or austenitic structures.
(4) Mechanical properties of sintered manganese steel are much affected by repressing and resintering treatments. Tensile strength of about 35-40kg/mm2, elongation of about 8-13%, and impact energy of about 2-6kg-m/cm2 can be obtained for austenitic manganese steel.
