METHOD FOR MANUFACTURING Ni GROUP FORGED ALLOY MATERIAL

To provide a method for manufacturing an Ni group forged alloy material having balanced tensile characteristics and creep characteristics at a higher level than a conventional level.SOLUTION: A method for manufacturing an Ni group forged alloy material includes: a dissolving/casting step of dissolving/casting a raw material and forming an alloy ingot; a pseudo homogenization heat treatment step of subjecting the alloy ingot to soaking treatment of heating it to a predetermined temperature and then cooling it to 700°C, and preparing a pseudo homogenized alloy ingot in which eutectic reaction γ' phase grains in a range of 1-15 vol.% are left between crystal grains of a γ phase; a forging step of forging the pseudo homogenized alloy ingot, and forming a forging molding material having an average particle diameter of the eutectic reaction γ' phase grains of 2-40 μm; a solution/crystal coarsening heat treatment step of heating the forging molding material, subjecting a precipitation phase other than the eutectic reaction γ' phase grains to solution heat treatment, and preparing a re-crystallization coarsening material obtained by re-crystallization coarsening the γ phase so as to have an average crystal particle diameter of 15-200 μm; and an age heat treatment step of precipitating an age precipitation γ' phase particles in the γ phase of the re-crystallization coarsening material.SELECTED DRAWING: Figure 1 【課題】引張特性とクリープ特性とが従来よりも高いレベルでバランスしたNi基鍛造合金材の製造方法を提供する。【解決手段】原料を溶解・鋳造して合金鋳塊を形成する溶解・鋳造工程と、該合金鋳塊に対して所定温度に加熱した後に700℃まで冷却するソーキング処理を施して、γ相の結晶粒の間に共晶反応γ'相粒を1〜15体積％の範囲で残存させた擬均質化合金鋳塊を用意する擬均質化熱処理工程と、該擬均質化合金鋳塊に対して鍛造加工を施して前記共晶反応γ'相粒の平均粒径が2〜40μmとなる鍛造加工成形材を形成する鍛造加工工程と、該鍛造加工成形材を加熱して前記共晶反応γ'相粒以外の析出相を溶体化すると共に前記γ相を平均結晶粒径15〜200μmに再結晶粗大化した再結晶粗大化材を用意する溶体化・結晶粗大化熱処理工程と、前記再結晶粗大化材の前記γ相の中に時効析出γ'相粒を析出させる時効熱処理工程と、を有することを特徴とする。【選択図】図１