High-grade duplex stainless steel with much suppressed formation of intermetallic phases and having

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Formation of intermetallic phases such as sigma (σ) and khi (χ) shows detrimental effects on the corrosion and mechanical properties of high-grade duplex stainless steel. The present invention provides high-grade duplex stainless steel with much suppressed formation of intermetallic phases, of which the chemical composition consists essentially, on a weight basis, of : Cr : 21.0%˜38.0%, Ni : 3.0%˜12.0%, Mo : 1.5%˜6.5%, W : 6.5% or less, Si : 3.0% or less, Mn : 8.0% or less, N : 0.2%˜0.7%, C : 0.1% or less, at least one element selected from the group consisting of Ba : 0.0001˜0.6% and one or more elements of Mischmetal (MM) and Y : 0.0001˜1.0% in total, and a balance of Fe and incidental impurities. The pitting resistance equivalent has a value of 40≦PREW≦67 defined by the following formula (1) : [in-line-formulae]PREW=wt. % Cr+3.3(wt. % Mo+0.5 wt. % W)+30 wt. % N  ((1)[/in-line-formulae] The present high-grade duplex stainless steel exhibits an excellent corrosion resistance, embrittlement resistance, castability and hot workability.