Patent ID: 8506729

Claim:
An austenitic stainless hot-rolled steel material having a superior corrosion resistance and a low-temperature toughness, comprising: C: not more than 0.03 mass %; Si: more than 0.3 mass % and not more than 1.5 mass %; Mn: 0.1 to 3.0 mass %; P: not more than 0.05 mass %; S: not more than 0.003 mass %; Ni: 15.0 to 21.0 mass %; Cr: 22.0 to 28.0 mass %; Mo: 1.5 to 3.5 mass %; N: 0.15 to 0.35 mass %; Al: 0.005 to 0.1 mass %; O: not more than 0.007 mass %; and a remnant of the steel material comprising Fe and substantially inevitable impurities and a content of intermetallic compounds contained in the steel material is not more than 0.5 mass %, wherein a PI value expressed by the following formula ranges from 35 to 40: PI=Cr+3.3(Mo+0.5W)+16N; and a δcal value expressed by the following formula ranges from −6 to +4: δ cal=2.9(Cr+0.3Si+Mo+0.5W)−2.6(Ni+0.3Mn+0.25Cu+35C+20N)−18, wherein a value by each element represents the content of the element expressed in terms of mass %.