Daido Steel Co., Ltd.

Kenta Yamashita

Shigeki Ueta

Kohki Izumi

Shuji Narita

Youhei Hoshi

Yasuhiro Sawada

The present invention relates to a method for manufacturing a round-rod shaped alloy ingot by hot forging, containing suspending a primary alloy ingot having a round-rod shape in a columnar mold while one end of the primary alloy ingot is held, pouring a molten metal formed of a heat-retaining metal into the columnar mold so as to apply a coating of the heat-retaining metal to the entire circumference of the primary alloy ingot, to obtain a forging alloy ingot, taking the forging alloy ingot out from the columnar mold, then subjecting the forging alloy ingot to a hot forging while an end portion of the forging alloy ingot is gripped as a gripping portion, and removing the coating of the heat-retaining metal.

Method for manufacturing alloy ingot

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.

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Shibukawa, Japan

Kenta Yamashita