Abstract
N-155 alloy and the same alloy with 10% Ni replaced with equal amount of Mn were selected as the base composition and about twenty alloys containing various amounts of carbon and nitrogen were melted.
The reasons why not only the forgeability is improved by the addition of manganese, but also an excellent high temperature property is obtained by the addition of proper amounts of carbon and nitrogen were explored.
Results obtained were as follows.
(1) If the carbon and nitrogen contents are nearly equal, the solidifying temperature and the solution temperature of the precipitates drop, the deformation resistance becomes lower and the cast structure more easily disappears in the high manganese alloys than in N-155 type alloys.
The reasons why the high manganese alloys are more easily forged than the N-155 type alloys, lie in these facts.
(2) The fact that the softening resistance property of the high manganese alloys is more excellent than that of the N-155 type alloys, is due to the fact that the age hardening property of the former is superior to that of the latter.
The reason why the high manganese alloys have an excellent high temperature property, though they are easily forged, is given by the above-mentioned fact.
