Resistance to oxidation by austenitic stainless steels

High focus is given to the feasibility of stainless steels with air or oxygen. However trends in the design of steam and other forms of power production have grown more interest in the oxidation in carbon monoxide and water vapor.  Subjecting to the nominal conditions to the leads of the development of security layer as mentioned earlier, however when conditions are severe, layer damage may occur. The beginning of this variation is unpredictable and sensitive to alloy’s chemistry.

Although, the reaction mechanisms are identical to in air, oxygen, water vapor and carbon dioxide reaction rates may vary considerably. For instance, identical scaling behavior has been found in air and oxygen except that scale damage occurs faster in oxygen.

Because, the results occurred in air could be implemented carefully while considering service in pure

oxygen. An increased corrosion rates can be in the presence of water vapor that creates an effect of damped air on the oxidation of stainless steel 330. The higher nickel magnitude in steel type 330 is less prone to the moisture effects therefore it is noticed that higher chromium and nickel content offers greater service temperature in damped air. The steel types 330 service supremely at temperatures above 1800oF and services at temperatures about 2000oF. The addition of moisture to oxygen significantly improves the corrosion rates of SS 304 and 316, the temperature limits can be maintained at the nominal levels.

It is hard to mention the maximum operation temperatures for steam operation, a reason is the sensitivity of corrosion rate because of surface condition, the smooth cold treated surfaces reduce the corrosion effects in the steam services. The austenitic stainless steel grades can serve at temperatures about 1600oF or 871oC at the higher temperatures.

The steel types 304 and 321 are used in the mild pressure steam units at temperatures around 1400oF or 760oC. The security layer on type 304 and 316 exfoliate at the high temperatures. The oxidation of steel grades in carbon dioxide and carbon monoxide media at 1100 – 1800oF due to their service in the gas quenched nuclear reactors. Wide evaluation on the steel oxidation in availability of carbon dioxide at temperatures above 1200oF to 1800oF were performed, the outcomes describe the oxidation in steel type 304 in Carbon dioxide at 1 atm at the different temperature limits.

The steel type 406 provides supreme resistance to corrosion by carbon dioxide at 1700oF or 927oC, specifically because of aluminum concentration. Moreover, it appears that the higher magnitude of nickel improves the oxidation resistance in carbon dioxide media. For services in CO2, the scaling temperature limits for steel types 302, 321, 347, 410 and 430 should be adjusted about 100 to 200oF or up to 93oC, although the chromium-nickel grades like concentrated stainless steel 310 and SS 330 can be utilized at temperatures for service in air.

The austenitic stainless steels offer average service in the high temperature oxidizing media. Commonly used steel grades are stainless steel 304, steel 309, steel 316 and steel type 330.