摘要 |
A cast steel of superior corrosion resistance and high strength comprises 0.1% C, 1.5% Si, 2% MN, 0.04% S, 17-20% Cr, 3-7% Ni, 1.5-2.5% Mo, 5-7% Cu, 0.1% N and balance Fe. The steel is soln.-treated at 90-1150 degrees C, heat-treated at 600-700 degrees C, quenched, and pptn. hardened by heating at 450-600 degrees C. The steel, which contains an av. amt. of Cr and less Ni than conventional stainless steel, exhibits improved resistance to the attack by strong acids. It is used for heat exchanger tubes and esp. for suction roll shells in papermaking machines. |