PRODUCTION OF LOW-CARBON ALUMINUM KILLED STEEL OF HIGH NITRATE STRESS CORROSION CRACKING RESISTANCE

摘要

PURPOSE:To obtain low-carbon aluminum killed steel of high nitrate stress corrosion cracking resistance by heating steel contg. low content of C and specific amts. of Si, Mn, SolAl and Nb to specific temps., then tempering the same. CONSTITUTION:Steel consisting of 0.003-0.07% C, =0.5% Si, 0.3-3.0% Mn, 0.01-0.10% SolAl, Nb (7-15)XC%, and the balance Fe with unavoidable impurities and, if necessary, added with 0.01-0.50% Zr, and 0.01-0.50% Ti is heated to Ac3 point -1,150 deg.C, after which it is tempered. this method decreases the amt. of C in the steel compsn., further immobilizing harmful solid solubilized C and N to Nb and further to carbonitrides by addition of Nb or further Zr and Ti, and forming fine grains by addition of Al, thereby assuring the good resistance to nitrate stress corrosion cracking. This low carbon aluminum killed steel is used for high temp. furnace shells or the like.