CORROSION OF STEELS IN LIQUID BISMUTH AND LEAD

The corrosion of a variety of steels in liquid lead and bismuth was studied in the temperature range 600 to 900 deg C by measuring weight losses of steel pins after immersion in the hot side of a thermal convection loop. In uninhibited bismuth, low-alloy steels are more resistant to corrosion than 13% Cr- Fe or 18-8 stainless steel. Both nickel and manganese have an equally deleterious effect on the corrosion resistance of 21~% Cr-1% Mo steel. In bismuth inhibited with zirconium the best steels tested had extrapolated corrosion rates less than 0.005 in./year at 700 deg C with a 50 deg C temperature differential. The corrosion of steels in unihibited lead is about 40 times less than in uninhibited bismuih under similar conditions, and the corrosion is reduced by addition of 500 ppm titanium, with the same order of steel resistance as for the inhibited bismuth test. (auth)