GAS TURBINE DISK MATERIAL AND HEAT TREATMENT METHOD THEREFOR

1 . A gas turbine disk material comprising, by mass %:

C: from 0.05 to 0.15%;

Ni: from 0.25 to 1.50%;

Cr: from 9.0 to 12.0%;

Mo: from 0.50 to 0.90%;

W: from 1.0 to 2.0%;

V: from 0.10 to 0.30%;

Nb: from 0.01 to 0.10%;

Co: from 0.01 to 4.0%;

B: from 0.0005 to 0.010%;

N: from 0.01 to 0.05%;

Mn: 0.40% or less;

Si: 0.10% or less; and

Al: 0.020% or less, wherein

a balance is of Fe and unavoidable impurities.

2 . The gas turbine disk material according to claim 1 , wherein

a ratio of N content [N %] to Al content [Al %], [N %]/[Al %], is 2.4 or greater.

3 . The gas turbine disk material according to claim 1 , wherein

a B equivalent ([B %]+0.5 [N %]) expressed as a sum of content B [B %] and 0.5 times of content N [N %] is from 0.0055 to 0.030%.

4 . The gas turbine disk material according to claim 1 , wherein

an absorption energy in a room temperature Charpy impact test is 40 J or greater.

5 . The gas turbine disk material according to claim 1 , wherein

a creep rupture time at 596° C.×310 MPa is 750 hours or more.

6 . A heat treatment method for a gas turbine disk material, wherein

when a heat treatment of heating and quenching a forged material having the component composition according to claim 1 and then tempering the forged material is implemented, a quenching heating temperature is set within a range from 1050 to 1150° C.

7 . The gas turbine disk material according to claim 1 , wherein

a Ni content is 0.79 to 1.50% by mass.

8 . The gas turbine disk material according to claim 1 , wherein

a Cr content is 10.17 to 12.0% by mass.

9 . The gas turbine disk material according to claim 1 , wherein

a content of the unavoidable impurities is 0.015% or less by mass.