NI-BASE ALLOY EXCELLENT IN GRAIN BOUNDARY CORROSION RESISTANCE

摘要

PURPOSE:To provide a Ni-base alloy enhanced in grain boundary corrosion resistance, by specifying the contents of Ni, Cr, Fe, Mo, Cu, Mn and W in a base composition while limiting the contents of C and Si in impurities. CONSTITUTION:An Ni-base alloy comprising, on the weight basis 21-26% Cr, 13-24% Fe, 5-8% Mo, 1.5-2.5% Cu, 0.1-1.0% Mn, 0.1-1.5% W, according to necessity, 0.1-5.0% Co, further, one or more of 0.05-0.5% Ti, Nb, Zr, V or Hf and the remainder Ni and inevitable impurities. The content C as an impurity in this alloy composition is limited to 0.015% or less and the content of Si to 0.05% or less. By limiting the compositional range and impurities, excellent corrosion resistance can be obtained and excellent grain boundary corrosion resistance can be held even if annealing treatment is applied at about 600-950 deg.C. This Ni-base alloy is used in the structural member of a chemical plant.