Austenite-type stainless steel hot-rolling steel material with excellent corrosion resistance, proof-stress, and low-temperature toughness and production method thereof

摘要

An austenitic stainless steel hot-rolled steel material can be provided which has sea-water resistance and strength superior to conventional steel. Low-temperature toughness can be maintained, which is preferable in a structural member of speedy craft. The steel material can include an austenitic stainless steel hot-rolled steel material which excels in the properties of corrosion resistance, proof stress, and low-temperature toughness. In such austenitic stainless steel hot-rolling steel material, e.g., PI [=Cr+3.3(Mo+0.5W)+16N] ranges from 35 to 40, delta cal [=2.9 (Cr+0.3Si+Mo+0.5W)-2.6 (Ni+0.3Mn+0.25Cu+35C+20N)-18] ranges from -6 to +2, and a 0.2% proof stress at room temperature is not less than 550 MPa, Charpy impact value measured using a V-notch test piece at -40° C. is not less than 100 J/cm2, and the pitting potential measured in a deaerated aqueous solution of 10% NaCl at 50° C. (Vc'100) is not less than 500 mV (as it relates to saturated Ag/AgCl).