Ni-based alloy for hot-working die, and hot-forging die using same
Provided are a Ni-based alloy for hot die having a high high-temperature compressive strength and a good oxidation resistance and being capable of suppressing the deterioration in the working environment and the shape deterioration, and a hot forging die made of the Ni-based alloy for hot die. The Ni-based alloy for hot die comprises, in mass %, W: 7.0 to 15.0%, Mo: 2.5 to 11.0%, Al: 5.0 to 7.5%, Cr: 0.5 to 3.0%, Ta: 0.5 to 7.0%, S: 0.0010% or less, one or two or more selected from rare-earth elements, Y, and Mg in a total amount of 0 to 0.020%, and the balance of Ni with inevitable impurities. In addition to the composition described above, one or two elements selected from Zr and Hf can further be contained in a total amount of 0.5% or less.
1. A Ni-based alloy for a hot forging die, consisting of, in mass %,
W: 10.0 to 15.0%,
Mo: 2.5 to 11.0%,
Al: 5.0 to 7.5%,
Cr: 0.5 to 3.0%,
Ta: 0.5 to 7.0%,
S: 0.0010% or less,
at least one element selected from rare-earth elements, Y, and Mg in a total amount of 0 to 0.020%,
optionally, one or two elements selected from Zr and Hf in a total amount of 0.5% or less,
optionally, one or two elements selected from Ti and Nb in a total amount of 3.5% or less, a total content of Ta, Ti, and Nb being 1.0 to 7.0%,
optionally, Co: 15.0% or less,
optionally, one or two elements selected from C: 0.25% or less and B: 0.05% or less, and
the balance of Ni with inevitable impurities.
2. The Ni-based alloy for a hot forging die according to claim 1 , wherein one or two elements selected from Zr and Hf is present in a total amount of 0.5% or less.
3. The Ni-based alloy for a hot forging die according to claim 1 , wherein one or two elements selected from Ti and Nb is present in a total amount of 3.5% or less, wherein a total content of Ta, Ti, and Nb is 1.0 to 7.0%.
4. The Ni-based alloy for a hot forging die according to claim 1 , wherein Co is present at 15.0% or less.
5. The Ni-based alloy for a hot forging die according to claim 1 , wherein one or two elements selected from C: 0.25% or less and B: 0.05% or less is present.
6. The Ni-based alloy for a hot forging die according to claim 1 , wherein 0.2% compressive strength at a test temperature of 1000° C. and a strain rate of 10 −3 /sec is 500 MPa or more.
7. The Ni-based alloy for a hot forging die according to claim 1 , wherein 0.2% compressive strength at a test temperature of 1100° C. and a strain rate of 10 −3 /sec is 300 MPa or more.
8. The Ni-based alloy for a hot forging die according to claim 1 , wherein Co is not present, and Mo is 4.9 to 11.0% by mass.
9. The Ni-based alloy for a hot forging die according to claim 1 , wherein Mg is 0.0010% or more.