Daido Steel Co., Ltd.

Kohki Izumi

Shigeki Ueta

Mototsugu Osaki

Kenta Yamashita

Shuji Narita

The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 0.3% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, Ti: more than 1.0% and less than 3.0%, and Ta: 0.01% or more and less than 2.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5&#x2264;([Ti]+[Nb]+[Ta])/[Al]&#xd7;10&#x3c;6.5 and 9.5&#x2264;[Al]+[Ti]+[Nb]+[Ta]&#x3c;13.0.

Ni-based superalloy for hot forging

The present invention relates to a method for producing a precipitation strengthened Ni-based superalloy material having a predetermined composition, containing a blooming forging step of performing a forging at a temperature range of from Ts to Tm and performing an air cooling to form a billet having an average crystal grain size of #1 or more, an overaging thermal treatment step of heating and holding the billet at a temperature range of from Ts to Ts+50&#xb0; C. and slowly cooling it to a temperature of Ts or lower, and a crystal grain fining forging step of performing another forging at a temperature range of from Ts&#x2212;150&#xb0; C. to Ts and performing another air cooling, in which Ts is from 1,030&#xb0; C. to 1,100&#xb0; C., and an overall average crystal grain size is #8 or more after the crystal grain fining forging step.

Method for producing Ni-based superalloy material

The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 2.0% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, and Ti: more than 1.0% and less than 3.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5&#x2264;([Ti]+[Nb])/[Al]&#xd7;10&#x3c;6.5 and 9.5&#x2264;[Al]+[Ti]+[Nb]&#x3c;13.0.

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Nagoya, Japan

Kohki Izumi