Method for producing ni-based alloy

A method for producing a Ni-based alloy, the method comprising hot forging a Ni-based alloy material having a composition comprising, by mass, 0.02 to 0.10% of C, 0.15% or less of Si, 0.1% or less of Mn, 0.015% or less of P, 0.015% or less of S, 18 to 21% of Cr, 3.5 to 5.0% of Mo, 12 to 15% of Co, 0.1% or less of Cu, 1.2 to 1.6% of Al, 2.75 to 3.25% of Ti, 2% or less of Fe, 0.003 to 0.01% of B, and 0.02 to 0.08% of Zr, the balance of Ni with impurities,

• wherein the hot forging is performed at a time when a temperature of the Ni-based alloy material is at least 900° C. while the Ni-based alloy material heated to a preheating temperature of T1 to T2° C. is reduced in temperature,
• wherein a temperature decrease rate of the Ni-based alloy material during the temperature reduction from the preheating temperature to 900° C. is 2.0° C./second or less, and
• wherein T1 is a temperature at which all γ′ phases are in solid solution in a matrix phase of the material, and T2 is a temperature at which the matrix phase of the material starts to melt.