Research On High Temperature Corrosion And High Temperature Oxidation Behavior Of Austenitic Stainless Steel

With the rapid growth of China's population and the improvement of people's living standards,the output of urban domestic waste has gradually increased.Since waste incineration power generation is a clean and efficient way of energy reuse,it not only increases power generation,but also reduces carbon emissions.Therefore,waste incineration treatment accounts for an increasing proportion of waste treatment.The waste incinerator has been processing waste at extremely high temperatures.In order to ensure that the waste incineration equipment can be used for a long time and can be used at high temperatures,it is necessary for the waste incinerator materials to have strong high temperature resistance.Therefore,Reasonable selection of materials for waste incinerators is a very important task.In the past,waste incineration equipment mainly used traditional stainless steel,nickel-based alloys and low-alloy steels as incinerator materials.Although nickel-based alloys have better corrosion resistance,they are costly.Although the cost of the other two steels is low,they have poor heat and corrosion resistance due to their low alloy content.Therefore,super austenitic stainless steel has attracted a growing number of researchers'attention due to its extremely high corrosion resistance and relatively low cost.The most serious damage to the internal water wall and superheater of the incinerator material in the garbage combustion process is mainly the corrosive medium containing chlorine,and the non-heated surface material also suffers from high temperature oxidation.Therefore,this paper uses 254SMo,904L super austenitic stainless steel and 317L austenitic stainless steel as the research objects to simulate the environment of the waste incinerator,and specifically studies the thermal corrosion and high temperature oxidation of the three materials at high temperatures.(1)254SMo,904L and 317L were subjected to hot corrosion experiments at 750?,850?and 950?in Na Cl medium,and the hot corrosion time was 60 h.With the increase of temperature,the corrosion of materials is also intensified.No intergranular corrosion is observed in the cross-sections of the three materials at 750?,and the intergranular corrosion is observed in the cross-sections of the three materials at 850?and 950?.Intergranular corrosion,and the intergranular corrosion of 317L austenitic stainless steel is the most serious.At 950?,the weight loss of the three materials all reached the maximum.The weight loss of254SMo and 904L austenitic stainless steel was about 180 mg/cm~2,and the corrosion weight loss of 317L reached 277.79 mg/cm~2.The corrosion was very serious.The corrosion degree of the three austenitic stainless steels is 317L>904L>254SMo in descending order.The hot corrosion of austenitic stainless steel follows the“active oxidation”mechanism,and the generated chlorine gas will participate in the reaction.(2)The high-temperature oxidation behavior of three austenitic stainless steels in static air at 750?,850?and 950?is studied.By recording the weight of the material,a high-temperature oxidation kinetic curve is obtained.In the initial stage of oxidation,the oxidation kinetic curve follows a linear law.As the temperature increases,so does the weight of the material.The surface morphology,phase composition,cross-sectional morphology and composition distribution of the three materials were analyzed by XRD and SEM/EDS.It was found that the surface oxide films of 254SMo and 904L super austenitic stainless steels were relatively dense.At the three temperatures,the surface oxide film of the three austenitic stainless steels showed no signs of shedding,but the cross-sectional view shows that the surface oxide film of the 317L austenitic stainless steel is loose.(3)254SMo,904L and 317L were subjected to high temperature oxidation studies in flowing oxygen at 750?,850?and 950?.When the three materials are oxidized at high temperature,when the oxygen flow rate in the tube furnace is 10 m L/min,the weight of the material increases with the increase of temperature,the weight increase is very obvious,and the oxidation kinetics curve roughly follows the linear law.When the temperature is 750?,no signs of scale peeling are observed on the surface of 254SMo,a small amount of scale peeling off on the surface of 904L,a large amount of scale peeling can be clearly seen on the surface of 317L austenitic stainless steel,and the surface of three austenitic stainless steels is oxidized.The membranes are relatively loose.When the temperature is 850?and 950?,the three materials are violently oxidized at high temperature,and the oxide film is peeled off in the crucible in lumps.The average weight gain of high-temperature oxidation at 950?is 53.3times that of 750?.