The high temperature oxidation resistance is the key performance index of the heat-resistant stainless steel, and it is paid close attention to by the people in the industry. Stainless steel containing special alloy elements is an important factor to enhance and improve the oxidation resistance of the alloy, the prerequisite to guarantee the basic properties of stainless steel material, adding proper amount of alloy elements can improve the alloy oxidation resistance, surface oxidation because it can form a layer of compact protective film on stainless steel surface, so as to enhance the high temperature oxidation resistance stainless steel material.
The heat resistant stainless steel 310S is high chromium and high nickel austenitic stainless steel, it not only has relatively good corrosion resistance and mechanical ability, but also has excellent excellent high-temperature oxidation resistance and creep resistance. Therefore, it is also used to make a large number of high temperature furnaces and high temperature components in special environment.
Through the high temperature oxidation mechanism of the heat-resistant stainless steel 310S, there is a good breakthrough in the research. The high temperature oxidation test of 310S stainless steel in air was carried out to evaluate its high temperature oxidation resistance. Based on the analysis of the oxidation kinetics gain curve, the morphology, distribution and structure of these oxide films were studied, and the formation mechanism of the oxide film was explained.
The test sample is the hot rolled stainless steel 310S plate of the austenitic stainless steel. The chemical composition is 0.055 carbon, 0.50 silicon, 1.03 manganese, 25.52 chromium and 19.25 nickel.
The 310S stainless steel samples were cut into 30mm * 15mm * 4mmm. 3 parallel samples were used at each test point, the samples were lapping, and the surface oxide scale and the cutting edge were removed by sandpaper, then washed and dried by ethanol. Prepare the same number of crucibles with the same number of samples and bake them with a resistance heating furnace, so that the residual substances in the crucible can be fully developed and the quality is constant. The high temperature oxidizing specimens were directly placed in the crucible and placed together in a box type resistance furnace for high temperature oxidation. The test atmosphere is air, and the oxidation temperature is 800, 900 and 1000, respectively. The treatment time of each sample is 20, 40, 60, 80, 100, 120 and 140h, respectively. After the oxidation is completed, weighing and recording, the weighing instrument is the balance of the electronic analysis.
After the high temperature oxidation test was finished, the oxidation products were analyzed by X ray diffractometer, and then the surface morphology of the oxide film was analyzed by scanning electron microscope and energy dispersive spectrometer. The final results show that the heat-resistant stainless steel 310S has a very good oxidation resistance at 800, 900, and 1000 C. With the prolongation of the temperature, there are different degrees of oxidation aggravation, but the trend of oxidation slows down with time. In addition, with the increase of temperature, the rate of oxidation will be accelerated.
The second point is that the oxide film is composed of outer layer of dense spinel MnCr2O4, Cr2O3 and inner SiO2. As the temperature continues to rise, the diffraction peak of MnCr2O4 will increase, and the resultant will also become more. The multi-layer compact structure and the good oxidation resistance of the oxide itself can make the heat-resistant stainless steel 310S exhibit excellent high temperature oxidation resistance as a whole.
Source: China Stainless Steel Plates Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)