310 S Stainless Steel Spray Gun In The Rich Lead Slag Corrosion Speed Of Experimental Research

The paper is aim at serious corrosion problem of stainless steel spray gun in molten lead-rich slag making use of stainless steel high-temperature corrosion theory under engineering materials high temperature corrosion behavior as the background. The measure of decreasing310S stainless steel corrosion speed in molten lead-rich slag is researched according to the corrosion law, which is an important guiding significance to extend service life of ISA furnace spray gun.The corrosion law of310S stainless steel in the molten lead-rich slag is as follows:The relation of corrosion rate and corrosion time conform to linear rule as " induced stage" and "autocatalytic stage" when static corrosion and dynamic corrosion of310S stainless steel occur in the lead-rich slag at1150℃. The relation of corrosion rate Re and corrosion time is as follows:The static corrosion:induced stage Rc=0.31t; autocatalytic stage Rc=5.88t-50.59.The dynamic corrosion:induced stage Re=0.0631; autocatalytic stage Rc=4.77t73.42.The relation of corrosion rate Re and corrosion time in the lead-rich slag between1000℃and1075℃accords with linear rule too.which is as follows:1000～1075℃Rc=0.016t-0.373;1075～1200℃Rc=0.103t-93.054.1065℃is mutation temperature of corrosion rate.The measures of decreasing310S stainless steel corrosion speed in molten lead-rich slag are as follows:(1) Adding high temperature oxidation resistance coating on310S stainless steel. Experiments find that lmm thickness coating of aluminum phosphate chromium adhesive SiC can delay310S stainless steel entering into " induced stage" and "autocatalytic stage" ablut3hours. But1mm thickness coating of plasma spraying SiC can delay20hours, which is nearly7times than coating of aluminum phosphate chromium adhesive SiC. The coating of plasma spraying SiC is able to effectively decrease310S stainless steel corrosion speed.(2) Another measure is lowering spray gun heat from molten lead-rich slag by lead-rich slag layer. Through the calculation of310S stainless steel spray gun heat transfer progress and balance, it is found that molten lead-rich slag can form a layer of lead-rich slag ontside spray gun wall if the heat of outer wall is taken above5.374J/(cm2·min). This measure not only protects spray gun from high temperature crossion of molten lead-rich slag, but also lowers crossion temperature of spray gun. It is also found that lead-rich slag adhering to310S stainless steel can reduce spray gun heat below1065℃and delay spray gun entering into " induced stage" and "autocatalytic stage" about12hours.whic effectively decreases crossion speed of310S stainless steel spray gun.The heat-conducting property of lead-rich slag is related with its coefficient of thermal conductivity. The coefficient of thermal conductivity of lead-rich slag inscreases with the addition of Pb contents and its temperature after experiment determination, which it accords with linear rule between600℃and950℃:48.70%Pb contents:λ=1.04×10-3t+0.19444.16%Pb contents:λ=9.22×10-4t+0.148However, its coefficient of thermal conductivity will sharply rise at near softening temperature, which not accords with linear rule. The coefficient of thermal conductivity of48.70%Pb contents lead-rich slag is1.316W·m-1·K-1at1000℃and1.438W·m-1·K-1at1020℃.