Influence of Gaseous Media Flow in the Dual Ar-H2-H2O/air Atmosphere Setup on the Scale Growth Kinetics of Crofer 22APU Ferritic Stainless Steel

2016 ◽  
Vol 26 (2) ◽  
pp. 540-546 ◽  
Author(s):  
Mirosław Stygar ◽  
Juliusz Dąbrowa ◽  
Piotr Dziembaj ◽  
Tomasz Brylewski
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Growth Kinetics ◽  
Scale Growth ◽  
Air Atmosphere ◽  
Gaseous Media ◽  
Kinetics Of

scholarly journals HIGH TEMPERATURE OXIDATION OF AISI 439 FERRITIC STAINLESS STEEL IN SYNTHETIC AIR ATMOSPHERE

2018 ◽  
Vol 80 (5) ◽  
Author(s):  
Maria de Fatima Salgado ◽  
Jackeline Macêdo de Sousa Santos ◽  
Giscard Eanes Dias Viana ◽  
João Alberto Santos Porto ◽  
Gabriel de Souza Veras Fontinele ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Oxidation Kinetics ◽  
Principal Element ◽  
Oxidation Treatment ◽  
Temperature Oxidation ◽  
X Ray ◽  
Air Atmosphere ◽  
Steel Oxidation ◽  
Kinetics Of

Stainless steels may be used and exposed to aggressive gases at high temperatures. The oxidation behavior of AISI 439 ferritic stainless steel, was investigated by oxidation treatment at 850 ºC and 950 ºC, for 50h in Synthetic Air with 20% O2 atmosphere in a tubular oven and in a thermobalance. The oxidation kinetics of films are determined by measuring the mass versus oxidation time. The microstructure and chemical composition of the oxides were determined by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS).  Chemical analysis by EDS showed that films formed on AISI 439 stainless steel exhibited Cr as the principal element in the oxide film, in proportions to form the chromium oxide (Cr2O3) and the following elements: Mn, Fe, Ti and Si. Based on the oxidation kinetics, it was observed that steel oxidation follows the parabolic behaviour with increase in temperature and it produced the highest oxidation rate at 950 ºC and the lowest rate at 850 ºC. 

Effect of Water Vapor on Oxidation of Ferritic Stainless Steel 21Cr-0.6Mo-Nb-Ti in Simulated Reheating Environment

2013 ◽  
Vol 690-693 ◽  
pp. 280-289 ◽  
Author(s):  
Xia Wei Cheng ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Liang Hao ◽  
Jing Wei Zhao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Water Vapour ◽  
Ferritic Stainless Steel ◽  
Metal Interface ◽  
Water Vapour Content ◽  
Breakaway Oxidation ◽  
Temperature Oxidation ◽  
Air Atmosphere ◽  
High Oxidation Resistance ◽  
Very High

High temperature oxidation of ferritic stainless steel 21Cr-0.6Mo-Nb-Ti was carried out isothermally at 1100 oC under different water vapour content conditions in an electrical furnace. Water vapour does accelerate the formation of oxide scale of stainless steel 21Cr-0.6Mo-Nb-Ti, however, it is not significant. Some oxide grains consist of spinel crystal structure, which should be spinel Manganese Chromite. In dry air atmosphere, the grain of the spinel is more and bigger than that in wet air. No breakaway oxidation occurs in the experiment indicating that 21Cr-0.6Mo-Nb-Ti has very high oxidation resistance, which might be contributed by the formation of MnCr2O4and compact protective chromia. In addition, continuous silica formed along and accumulated at the oxide metal interface performs like a diffusion barrier.

Kinetic characterization of boride layers formed on AISI 316 stainless steel

2020 ◽  
Vol 62 (6) ◽  
pp. 652-656
Author(s):  
Özlem Aydın ◽  
Polat Topuz ◽  
Tuna Aydgomus
Keyword(s):  
Stainless Steel ◽  
Growth Kinetics ◽  
Optical Microscope ◽  
Boride Layer ◽  
Stainless Steel Surface ◽  
Image Analyzer ◽  
Surface Samples ◽  
Aisi 316 Stainless Steel ◽  
Aisi 316 ◽  
Kinetics Of

Abstract This paper presents the growth kinetics of the boride layer formed on a boronized AISI 316 (X5CrNiMo17-12-2) stainless steel surface. Samples were boronized applying the Ekabor 2™ boronizing agent in an atmosphere controlled furnace at 1073, 1173 and 1273 K for 1, 2 and 3 h by the powder pack method. Surfaces of the samples which have completed the boronizing process were prepared for metallographic examinations. An optical microscope and an integrated image analyzer were used to measure the thickness of the boride layer formed on the surface of the samples. Due to the dual phase structure of the boride layer formed on the steels in order to see these phases in detail, an SEM (Scanning Electron Microscope) image of the sample was taken with the help of the back scattered electrons. In addition, for determination of the elements constituting these phases, elemental analysis was carried out with the help of an EDS (Energy Dispersive Spectroscopy) unit connected to SEM. Then XRD (Xray diffraction analysis) analyses were carried out to understand in detail which phases formed the boron layer. For hardness measurements of boride layers, a Vickers hardness device with 100 g weight was used. Finally, to determine the growth kinetics of the boronized samples, calculations were made with the help of the Arhenius equation and compared with the literature.

Grain Growth in Nb-Alloyed Stainless Steel of AISI 347 during Heating

2013 ◽  
Vol 753 ◽  
pp. 345-348 ◽  
Author(s):  
Hai Wen Luo ◽  
Han Dong ◽  
Ling Feng Chen
Keyword(s):  
Activation Energy ◽  
Stainless Steel ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Isothermal Holding ◽  
Growth Exponent ◽  
Microalloyed Steels ◽  
Nb Content ◽  
Grain Growth Kinetics ◽  
Kinetics Of

Grain growth kinetics in an AISI 347 stainless steel with Nb content up to 0.7%wt was studied during the isothermal holding in the temperature range of 1100-1270°C for various periods. Abnormal grain growth was observed even in the presence of a large amount of precipitates. The kinetics of normal grain growth was tracked by metallographic measurements and fitted by the classical modeling, which led to two important parameters of activation energy Q and growth exponent n derived. Both of them are larger than the usual values for grain growth in the Nb-microalloyed steels due to the much larger content of Nb in the present steel.

Simulation of Line Annealing of Type 430 Ferritic Stainless Steel

2012 ◽  
Vol 715-716 ◽  
pp. 437-446
Author(s):  
Anna P. Kisko ◽  
Pasi P. Suikkanen ◽  
C. Isaac Garcia ◽  
K. Cho ◽  
M. Hua ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Fiber Orientation ◽  
Experimental Conditions ◽  
Metallographic Examination ◽  
Annealing Behavior ◽  
The Subject ◽  
Cold Rolled ◽  
Cold Worked ◽  
Kinetics Of

The annealing behavior of cold rolled Type 430 ferritic stainless steel is the subject of this paper. The steel was cold rolled 79%, then heated at 6 °C/s to the soaking temperature of 841 °C, which is just below the Ae1temperature. During heating, specimens were quenched from selected temperatures between 650 and 841 °C and after various times at 841 °C. These quenched samples underwent metallographic examination and micro-hardness determination. The results indicated that under the prevailing experimental conditions, the hardness appeared to correlate strongly with the extent of recrystallization. The kinetics of recrystallization appeared to originate in the cold worked state, where three kinds of grain were found: (i) smooth elongated, featureless of α-fiber orientation {001}<100>; (ii) irregular fishbone grains of the γ-fiber orientations {111}<112> plus {111}<110>; and (iii) twisted grains of the η-fiber orientation {001}<100>. It was found that the twisted grains of the η-fiber were the first to recrystallize, with the fishbone grains of the γ-fiber second, and the smooth elongated, featureless grains of the α-fiber last. It was found that the grains of the α-fiber orientation {001}<100> and the η-fiber orientation {001}<100> were replaced with grains of the γ-fiber orientations as recrystallization progressed. These results are discussed in terms of recrystallization and texture development.

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