PREPARATION OF HIGH ANTICORORSIVE FERRITE SYSTEM STAINLESS STEEL THAT ENSURE EXCELLENT ALKALI RESISTANCE STRESS CORROSION CRACK PROPERTY

摘要

PURPOSE:To ensure the excellent mechanical property of welded portions as well as a base metal portion and superior resistance to alkali stress corrosion crack, by hardening annealing ferrite system stainless steel not more than a specified temp. CONSTITUTION:High anticorrosive ferrite system stainless steel resisting alkali stress corrosion crack used for an evaporator of a NaOH purification plant, a heat exchanger of a boiler, to which boiler compound is charged, etc. is obtained by softening annealing ferrite system stainless steel in 0.03%=C, 1.00%=Si, 1.00%= Mn, 0.040%=P, 0.030%=S, 16.00-25.00% Cr, 1.50-3.50% Mo, 0.02%=N, 0.20%=Ni, 0.20%=Cu, remainder Fe and inevitable impurities at 1000 deg.C -preferably, not more than 900 deg.C, Heat treatment in the case when Ti is further added to said stainless steel is performed no more than 800 deg.C.