Oxidation Of Steel Research Articles

Oxidation Behaviour of Steel During hot Rolling by Using TiO2-Containing Water-Based Nanolubricant

The formation and performance of oxide scale on a low-alloy steel were investigated during hot rolling at 850 and 950 °C under various lubrication conditions, including benchmarks (dry condition and water) and water-based nanolubricants containing various concentrations of nano-TiO2 from 1.0 to 8.0 wt%. The results showed that the addition of nano-TiO2 particles in the lubricant significantly reduced the thickness of oxide scale and surface oxide roughness. The reduction reached the maximum when the concentration of TiO2 was 4.0 wt%. Detailed oxide phase characterisation and oxide component fraction determination revealed that hot rolling destroyed the conventional multi-layer oxide scale and promoted magnetite and haematite formation because of easy access of oxygen from the deformed structure. The effect of TiO2 was explained by the decrease in the rolling force, which led to a higher fraction of dense retaining wustite and therefore reduced the extent of further oxidation. Increasing temperature did not change the trend of lubrication effect but raised the rate of steel oxidation in general.

TEM study of the effect of high-temperature thermal cycles on the stability of the Y-Al-O oxides in MA956 ODS steel

MA956, a commercial ferritic grade of Oxide-Dispersion-Strengthened (ODS) steel, was investigated using transmission electron microscopy (TEM) to evaluate the influence of high-temperature thermal cycles on the nanometric dispersed oxides. Analyses of the oxide size distribution were carried out on foils from the as-received MA956 and following treatment at 1285 °C for one hour, and show that growth of the oxides has occurred under the thermal cycle. Implications for the oxide stability in the steel matrix are discussed, in the light of the oxide chemical composition.

Effect of oxygen partial pressure on oxidation behavior of ferritic stainless steel AISI 441 at high temperatures

In this investigation the oxidation behavior of AISI 441 stainless steel (SS) in the range from 850 °C to 950 °C was determined during 50 h in two different atmospheres: (a) synthetic air in a tubular oven; (b) argon with 1 ppm of O2 in a thermal balance. The oxidation kinetics was determined from the measured mass change as a function of oxidation time. Examination of the microstructure of the oxides and determination of their chemical composition were performed by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and glancing angle X-ray diffraction (GAXRD). Chemical analyses showed that films formed on the AISI 441 steel surface consisted mostly of chromium oxide but manganese, iron, titanium and silicon oxides were found in the oxidized layer. In synthetic air, the steel oxidation rate increased gradually as the temperature increased, but in the argon atmosphere with 1 ppm of oxygen, the highest oxidation rate was observed at 900 °C and the lowest at 950 °C.

The Breakdown of a 316L Stainless Steel Oxide Film in an AlCl3-EMIC Ionic Liquid

The Breakdown of a 316L Stainless Steel Oxide Film in an AlCl3-EMIC Ionic Liquid

Properties of High Temperature Oxidation of Heat-resistant Steel with Aluminium and Copper

The research is focused on a novel aluminum and copper-containing heat-resistant steel. The steel was designed by the material performance simulation software JmatPro, performed high-temperature oxidation tests at 650 °C and 700 °C atmospheric conditions, and analyzed the high-temperature oxidation processes and its mechanisms.The phase transtions and surface morphology of the oxide films were studied using X-ray diffraction (XRD), electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the equilibrium phase of the test steel is composed of γ phase and δ phase at 1050 °C and tranforms to tempered martensite and δ-Fe mixed structure after heat treatment. The preferential oxidation of Fe and Cr and the internal oxidation of Al occurred during the high temperature oxidation of the test steel. The oxide films were formed with various shape and weak bonding properties after high-temperature oxidation at 650℃. To the contrary, the oxide films more regular and evenly distributed, and has a certain protective effect after high-temperature oxidation at 700 ℃. The oxide films were divided into two layers, Fe2O3 is main element in the outer layer, the inner layer is mainly consisting the oxide of Cr. However, the addition of Cu element can promote the diffusion of Al and Si elements, which is beneficial to the formation of Al2O3 and SiO2 protective oxide films and excellent in high temperature oxidation resistance.

Data on Evaluation of the Corrosion Inhibition Effect of L-alpha-aminoisocaproate on High Carbon Steel Corrosion in Dilute Acid Media

Corrosion inhibition performance of l-alpha-aminoisocaproate on high carbon steel in 1 M HCl solution has been studied by weight loss measurement, open circuit potential measurement, optical microscopy and ATF-FTIR spectral analysis. The results showed the inhibition performance of l-alpha-aminoisocaproate is time dependent attaining an optimal value of 85.88 % at 5.63 % l-alpha-aminoisocaproate concentration (highest concentration) after 288 h of exposure. The corrosion potential plots of the high carbon steel at 0.91 % (lowest concentration) and 5.63 % l-alpha-aminoisocaproate concentration were more electropositive than the plots at 0% l-alpha-aminoisocaproate concentration due to the effective inhibition performance of l-alpha-aminoisocaproate in counteracting the oxidation of the carbon steel in the presence of chloride anions. Identified functional groups of alcohols, phenols, primary and secondary amines and amides, carboxylic acids, alkynes, aromatics, alkenes and alkanes consisting of O–H stretch, free hydroxyl, H–bonded, N–H stretch, –C(triple bond)C–H: C–H stretch, C–H stretch and =C–H stretch bonds where responsible for the corrosion inhibition. The optical morphology of the carbon steel after 7200 s of exposure in the acid solution without l-alpha-aminoisocaproate was severely corroded in contrast to the morphology of the steel in the presence of l-alpha-aminoisocaproate which underwent minor deterioration due to the time dependent action of the inhibitor.

Numerical simulation and experimental study on laser micromachining of 304L stainless steel in ambient air

The evolution of surface topography of 304L stainless steel, induced by a fiber laser with a wavelength of 1070 nm and a pulse width of 10 μs in ambient air, is studied experimentally in the fluence range between roughly 30 J/cm2 and 118 J/cm2. A two-dimensional (2D) transient model is developed to simulate the laser micromachining process of 304L stainless steel, which incorporates the heat and mass transfer as well as fluid flow. An oxidation kinetics model is established to describe the mass inflow caused by high temperature oxidation of stainless steel in both solid and liquid phases, and the oxygen concentration on the surface of the molten liquid is treated as a function of temperature and then applied to the expression of surface tension coefficient. A modified level-set method is developed to trace the free surface and consider the mass transfer caused by oxidation and evaporation, and the possible effects on the free surface boundary containing surface tension, recoil pressure, Marangoni effect and the shear stress caused by metallic vapor flow are coupled in the model. Based on this model, the impacts of laser fluence, ambient air and pulse duration on both laser micromachining processes and the evolution of surface topography from the bump to the crater are numerically investigated. Comparing the experimental results and the numerical results, the validity of the model is verified, and the formation mechanisms of both various topographies and phenomena during laser micromachining are analyzed. The results show that with the increase of laser fluence the irradiated zone presents the “flat-topped” bump, the “M-shaped” bump and the “Gaussian-like” crater successively. Furthermore, the mass inflow has a great influence on the topography of both the “flat-topped” bump and the “M-shaped” bump. Even though the surface tension considering oxygen concentration plays an important role in the formation of both the “M-shaped” bump and the “Gaussian-like” crater, evaporation largely determines the surface topography of the “Gaussian-like” crater at high laser fluences.

Oxidation and Electrical Behavior of Crofer 22APU Steel with the Co/Y2O3 Coating Produced by Direct Electroplating

Oxidation and Electrical Behavior of Crofer 22APU Steel with the Co/Y2O3 Coating Produced by Direct Electroplating

First-principles investigation of hydrogen behavior in different oxides in ODS steels

The energetics of single and multiple H atoms inside Y2O3, Y2Ti2O7, Y2TiO5, Y3Al5O12 and YAlO3 as well as the migration behavior of H atom have been investigated using first-principles calculations. Among these oxide matrixes, single H atom inside Y2TiO5 is most energetically stable, followed by Y2O3, Y2Ti2O7, Y3Al5O12 and YAlO3. The migration barrier of H atom in Y2O3 is lower than that in other oxide crystals. The formation energy and migration barrier of H atom in those oxide crystals are always higher than that in α-Fe. He atom is more stable than H atom inside oxide crystals, contrarily to the trend in α-Fe solid. Generally, in the cases of Hn (1 ≤ n ≤ 4) atoms inside oxide crystals, the formation energy of even-sized Hn cluster is lower than that of odd-sized Hn clusters, because two H atoms form a hydrogen molecule with strong H–H covalent bond.

Effect of Silicon Content on the Wear Behavior of Low-Carbon Dual-Phase Steels

The aim of this study is to understand the influence of the silicon content and volume fraction of martensite obtained by intercritical annealing at three temperatures (750, 780, and 800 °C) on the wear behavior of low-carbon dual-phase steels. Dry sliding wear tests were carried out in three sliding intervals (0–200, 200–600, and 600–1000 m) by using a pin-on-disk machine at normal load of 30 N, room temperature, and fixed sliding velocity of 0.5 m/s. The weight loss of the specimens was measured and the wear rate calculated. For all the samples, the wear rate decreased with increasing sliding distance. The results of the present investigation clearly show that the effect of the intercritical annealing temperature is greater than that of the silicon content. Among the three tested temperatures, the wear resistance was more sensitive to the silicon content at the lowest (750 °C). Both the content and hardness of the martensite were factors affecting the wear resistance of the dual-phase steels. The wear response of the samples can be described on the basis of the interaction between the martensite volume fraction and hardness. The role of the silicon content in the oxidation of steels was also examined.

Surface oxidation of nickel base alloys and stainless steel under pure oxygen atmosphere: Application to oxygen safety

Irradiation by a high power laser beam has been used since several years as an innovative approach for evaluating the reactivity of metallic materials with a pure oxygen atmosphere. Indeed, materials selection for oxygen service is a key factor of mitigating the ignition of equipment also called as oxygen fire. Pulled by the need having always more efficient industrial processes, the oxygen usages are evolving toward steadily higher pressures or temperatures. In such operating conditions, the evaluation of the metallic materials resistance to the oxygen fire ignition and their property to propagate based on the oxidation kinetic is the only way to avoid the oversizing of equipment. In this context, the use of laser in evaluating the reactivity of metallic materials is a well-adapted method enabling the accurate control of the energy deposition transmitted to the tested material during oxidation as well as giving access to the energy threshold required to trigger the oxygen fire ignition. This paper investigates the oxidation kinetics on nickel-based alloys (Inconels 600 and 625) and on stainless steel 310, using a laser or a furnace preheating on small metallic parts. The scope of the study is the oxidation step taking place before the heating of the sample up to its ignition temperature. Process parameters are oxygen pressure (1 and 40 barg), oxygen content (air versus pure oxygen), duration, and temperature. A numerical model is used to couple a sample surface condition (machined, sandblasted, polished) with laser parameters (power, duration) needed to reach a predetermined preheating temperature of the sample. In order to determine the threshold heat input for materials’ ignition by a laser in the oxygen atmosphere, it is necessary to know the absorption coefficient of the laser at the sample surface. This parameter is measured for various oxide layer thicknesses.

Effect of Si Content on the Corrosion Behavior of 420 MPa Weathering Steel

The effect of Si content (0.12%, 0.34%, and 0.48%) on the corrosion behavior of weathering steel in a simulated marine environment was investigated in a dry/wet alternating cycle corrosion experiment. Corrosion weight gain, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical methods were used to measure the regularity and nature of the rust. The results show that the corrosion process could be divided into an initial stage where the corrosion rate increased and a later stage where the corrosion rate decreased before remaining stable. The corrosion rate was the lowest for a Si content in the weathering steel of 0.48%. The corrosion products of all three steel groups contains α-FeOOH, β-FeOOH, γ-FeOOH, Fe3O4, and large amounts of amorphous compounds. Furthermore, Si benefits the transformation of β-FeOOH and γ-FeOOH to stable phases. The addition of the Si alloying element is beneficial to the formation of dense and compact rust layers that enhance the electrochemical resistance of weathering steel and silicon oxide influences the self-corrosion potential of the corrosion products.

Effect of current density on micro‐arc oxidation of Q235 steel and corrosion resistance in liquid Pb‐Bi

AbstractAn attempt has been made to improve the corrosion resistance in liquid Pb‐Bi by micro‐arc oxidation (MAO), and the effects under different current densities on the corrosion resistance of the coatings were discussed. Scanning electron microscope, energy dispersive spectrometer, and X‐ray diffraction were used to analyze the surface morphology and phase constituents of the MAO coatings produced under different current densities. The corrosion resistance of the coatings was evaluated by studying the element changes and morphology evolution. The results show that the compactness of the ceramic coating decreases with the current density increasing. In contrast to the performance of matrix metal, the ceramic coating exhibited a much better corrosion resistance in liquid Pb‐Bi. Moreover, the ceramic coating produced under current density of 10 A/dm 2 shows the best corrosion resistance.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЯ НАЧАЛЬНОГО ЭТАПА ОКИСЛЕНИЯ АУСТЕНИТНОЙ СТАЛИ 12Х18Н10Т В ВОДЯНОМ ПАРЕ

The paper presents the results of the study of the initial stage of oxidation of austenitic steel 12X18H10T in water vapor, which were obtained using a method of research of thin surface layers of steel, based on the analysis of nuclear reaction products in the interaction of oxygen with accelerated ion beams. Austenitic 18 % chromium steel 12X18H10T is one of the structural steels used in reactor installations with heavy liquid metal coolant (HLMC) in the region is relatively high (T<350 °C) temperatures. In test benches and experimental installations the temperature area of use of this steel is much wider. Studies of this steel, especially in the field of low temperatures or short time intervals of exposure of samples, where there are significant methodological difficulties, are of some scientific interest. In addition, the study of the oxidation of structural steels directly in gaseous media, including water vapor, are of great practical importance. It is because these modes of oxidation are used as special technological operations of formation of oxide films on the individual elements and the equipment of the first circuits of nuclear power plant (NPP) with HLMC on the basis of lead and its alloys.

Effects of carbon steel surface oxidation on critical heat flux in downward-face pool boiling

In this study, a downward-face pool boiling critical heat flux (CHF) experiment was performed using a carbon steel plate soldered to a copper base. The results of the experiment were analyzed and compared with those of a carbon steel and copper block experiment previously conducted at the same test facility. After polishing the surface using sandpaper, heat was applied to the surface by cartridge heating until CHF was attained. Due to the oxidation of the carbon steel, the surface changed gradually during boiling. The boiling cycle was repeated several times, and the CHF variations were observed. Detailed images of the heating surface behavior during boiling acquired by two synchronized high-speed cameras with different heat fluxes were analyzed. It was found that the more oxidized the surface became, the fewer bubbles were generated and the higher the CHF became; however, the bubble film departure frequency remained the same in all conditions. The contact angle and microscope surface images of the oxidation material were also obtained, and it was determined that the combined effect of the increase in wettability and decrease in nucleation site density was likely the reason that the CHF increased. This gradual oxidation process could be beneficial in actual situations since it can increase the upper limit of in-vessel retention external reactor vessel cooling.

Precipitation of various oxides in ODS ferritic steels

The reactive elements (Ti, Al and Zr) have been widely used for the improvement of the strength or the oxide resistance of ODS steels. In the present work, we studied the effect of the reactive elements on the precipitation of oxide particles, especially focusing upon the appropriate amount of the oxide composing elements, by addition of the large amounts of Y2O3 and reactive elements. The mechanically alloyed powders are annealed in a wide temperature range from 773 to 1423 K and then analysed by various analysis methods (small-angle X-ray scattering and X-ray diffraction by synchrotron radiation X-ray, scanning transmission electron microscope combined with energy dispersion X-ray spectroscopy, high-resolution transmission microscopy and 3D-atom probe). Ti, Al and Zr enhanced the growth of oxide particles, opposite to the many studies of Ti- and Zr-added ODS steels, as a result of the addition of Y2O3 and these elements ten times larger than those for usual use. The nucleation and growth of oxide particles are discussed by simulating the critical radius of nucleation and the growth based on the LSW theory. Y4Zr3O12 is stable and easy to precipitate even at lower annealing temperature. All reactive elements enhance the growth of oxide particles because of their big molar volume as compared to that of Y2O3.

Development of universal method for determining specific mass or thickness of scale crust on the surface of wire rod after continuous cooling

Problem statement. The production of various metal products using hot plastic deformation or heat treatment is inevitably linked to the processes of oxidation of steel because of its interaction with the air or atmosphere of the furnace. At the same time, changes occur in the chemical composition of the surface metal layer, the formation of oxides (scale), the transformation of their phase composition during the processing, which, in turn, depends on the temperature, speed and method of cooling the metal.The most widespread type of metal products, for which the scale is standardized not only by the requirements of the relevant standards, but also has a significant impact on the process of subsequent processing, is wire rod. The carbon steel scale, formed at high temperatures, consists of three oxides (FeO, Fe3O4 and Fe2O3), the actual content of which affects the formation of various density, and, consequently, different specific mass of scale with the same thickness of its layer on the rolled surface. In view of the fact that the known methods for determining the specific mass of the scale are rather laborious and require appropriate qualifications of technical personnel, there is a need to develop a universal method for qualitative and quantitative assessment of oxides formed on the surface of carbon steel, depending on changes in the technological parameters of production. Purpose. Development of a method for determining the specific mass or thickness of the scale layer formed on the surface of a wire rod of various diameters, with its actual chemical composition. Results. Based on the known chemical and physical patterns of processes occurring during high-temperature interaction of the surface of carbon steels and atmospheric air, a universal mathematical model has been developed that allows to elaborate one of the standardized quality indicators and it can be recommended as an alternative method for determining the specific mass or thickness of the scale on the surface wire rod in the research laboratories of metallurgical enterprises.

Distinct oxidation behaviour attributed to phase constitution transformation at different hot processing temperatures in Fe-10Mn-5.5Al-0.25C steel

Oxidation behaviour of Fe-10Mn-5.5Al-0.25C (wt.%) steel at 950–1150 °C has been investigated, which showed that oxidation resistance decreased largely with the elevated temperature. Phase constitution transformation included both the high-temperature austenite transformed into ferrite and into martensite. Phase constitution was modified by temperature which led to the transition of elements diffusing from the interface to volume diffusion, degrading the interface concentrations. The oxidation behaviour was changed from internal oxidation to homogeneous oxidation. The continuous and compact Al2O3 layers were more easily formed beneath inner oxide scales when oxidation at relatively low temperature and prevented further oxidation of the experimental steel.

Medium-Carbon Free-Cutting Steel

The paper presents theoretical and experimental studies of the formation processes of boron nitride, aluminium nitride, aluminium oxide and manganese sulphide inclusions in a free-cutting steel. Fact Sage software was used to model the behaviour of non-metallic inclusions. Formation temperatures and the amount of key inclusions in steel were calculated. Formation order of inclusions is as follows: aluminium oxide > boron nitride > manganese sulphide > aluminium nitride. The object of study was the A45AR grade steel in 1.1–1.2 kg ingots. It was melted in an induction furnace, and aluminium, nitrided ferrosilicon and ferroboron were added after deoxidation before tapping. Quality estimation included chemical composition, macro-and microstructure, the character and shape of non-metallic inclusions. The finished metal contained fine and uniformly distributed inclusions of boron nitride. Qualitative and quantitative analysis of boron nitrides distribution in metal matrix showed that they were present both as individual and complex compounds, mostly of spherical shape. The size of BN inclusions varied from 0.18 to 6.52 μm. The amount of boron added to steel did not affect the size of MnS non-metallic inclusions.

Investigation of Formation Features of Sulphide Inclusions and their Distribution inside the Grain Depending upon the Conditions of Steel 20 Deoxidation

The paper reports laboratory test findings on the impact of steel oxidation level on distribution features of non-metallic inclusions in low-alloyed structural steels. An analysis of the effect of various oxidation methods of steel on the distribution and formation of non-metallic inclusions is made. The results reveal a relation between the amount of sulphide and oxisulphide inclusions formed and steel oxidation level. The release of oxisulphide from the melt is accompanied with a decrease in the amount of both oxygen and sulphur. After oxygen content has achieved an equilibrium value, only “pure” sulphides are formed, which may deteriorate steel plastic properties. Thus, sulphides start precipitating only when oxygen content in the melt falls to a very low value. An increase in the amount of oxysulphides is accompanied with a decrease in sulphur concentration in the melt which reduces sulphide phase concentration at grain boundaries and stabilizes plastic properties. Thus the negative effect of sulphur can be reduced not only by decreasing its content in steel through expensive secondary steelmaking methods but also by controling the amount, shape and types of oxide, sulphide and oxisulphide inclusions in steel.