HIGH PURITY AND HIGH CLEANLINESS STAINLESS STEEL EXCELLENT IN GAP CORROSION RESISTANCE AND ANTI-RUST PROPERTY AND PREPARATION THEREOF

摘要

PURPOSE:To prepare the titled stainless steel excellent in processability and low in cost, by casting or heat treating molten steel having a specific composition consisting of C, Si, Mn, Cr, N, P, S, Al, O and Fe and prescribed in cleanliness at a specific temp. CONSTITUTION:Molten steel which contains 0.01-0.1% C, 3% or less Si, 2% or less Mn, 14-26% Cr, 0.005-0.2% N, 0.02% or less P, below 0.001% S, 0.02- 0.2% Al, below 0.003% O and, if necessary, further contains one or more of elements selected from 3% or less Mo, 2% or less Cu, 2% or less Ni, 0.6% or less Ti, 0.02-0.5% V, 0.02-0.2% Nb and 0.01% or less B and comprises the remainder of substantially Fe and has cleanliness comprising the sum of oxide type impurities and sulfide type impurities of 0.02 or less is continuously cast at a temp. of DELTAT deg.C=45 deg.C [DELTAT deg.C= (the temp. deg.C of molten steel in a tandish during continuous casting) - (the solidification temp. deg.C of molten steel)] to obtain a cast piece which is, in turn, heated to 1,230 deg.C or less or held thereto and the heated cast piece is hot rolled to obtain high purity and high cleanliness steel, excellent in gap corrosion resistance and anti-rust property.