| dc.description |
Brittleness in manganese steels can be associated with processing in a "wet¿
[micro]climate resulting in the formation of continuous oxide networks. The formation of
these networks can be prevented by sintering in an atmosphere, also ¿local¿ in a semiclosed
container, adhering to the Ellingham-Richardson oxide reduction criteria. When
this requirement is satisfied, however, further types of ductile ¿ brittle transitions are
observed. Rapid cooling, typically above 40°C/min, produces enough martensite to render
Fe-(3-4)Mn-(0·6-0·7)C material macroscopically brittle. Quenched and conventionally
tempered structures remain brittle. It is tentatively suggested that segregation of minor
alloying/tramp element(s), as in cast materials, is responsible for this temper
embrittlement. To overcome it, heat treatment at a temperature no higher than 200°C,
recovery/stress relief, is recommended. |
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