抄録
Ausaging behavior in 245kg/mm2 grade maraging steels has been investigated. Appreciable precipitation-hardening is produced by ausaging at temperatures below about 625°C. The precipitation hardening is considered to be due to relatively high titanium content. It is also observed that elongation and reduction of area are decreased with increasing ausaging temperature. The decrease in ductility is considered to be caused by the formation of coarse precipitates at the austenite grain boundaries. The coarse precipitates are greatly suppressed when ausaging temperature is decreased to about 550°C. After ausaging at 550°C from 3000min to 6000min, the following mechanical properties are obtained; ultimate tensile strength: 200-210kg/mm2, elongation: 10-15%, reduction of area; 60-65%. However, the ductility of specimens ausaged at 550°C for longer times tends to decrease because of the formation of relatively coarse precipitates at the austenite grain boundaries.
