The present invention relates to a Ni base alloy having sufficient strength at
high temperatures and high corrosion resistance at high temperatures in a high-temperature
composite corrosive environment in which chlorination or sulfidation occurs simultaneously
with high-temperature oxidation, without excessive cooling or surface protection.
According to the present invention, a Ni base alloy having high-temperature strength
and corrosion resistance includes Cr in a range of from 25 to 40 weight %, Al in
a range of from 1.5 to 2.5 weight %, C in a range of from 0.1 to 0.5 weight %,
W of 15 weight % or less, Mn of 2.0 weight % or less, Si in a range of from 0.3
to 6 weight %, Fe of 5% or less, and Ni of rest except inevitable impurities. When
strength at high temperatures is allowed to be small, W is in a range of from 0
to 8%, and Si is in a range of from 0.3 to 1% or from 1 to 6%. In order to enhance
strength at high temperatures, W is in a range of from 8 to 15, and Si is in a
range of from 0.3 to 1% or from 1 to 6%.
