Oxidation Resistance Of Steel Research Articles

The negative effect of V content on high temperature oxidation resistance of austenitic stainless steels at 850 °C

The effect of V on the high-temperature oxidation performance of austenitic stainless steel has been investigated by the constant-temperature oxidation weight gain approach, while the morphology, composition and elemental distribution of the oxide film are further analyzed by scanning electron microscopy and energy dispersive spectrum, transmission electron microscope and X-ray powder diffractometer as well as X-ray photoelectron spectroscopy, revealing the mechanism of the effect of V on the high-temperature oxidation performance of austenitic stainless steel. As a result, the addition of V has a significant adverse effect on the oxidation resistance of steel. Noteworthy, vanadium pentoxide generated during the oxidation process increases the internal stress of the surface oxide layer, reduces the integrity of the oxide layer and promotes oxygen penetration into the matrix. Simultaneously, the Z-phase formed at the grain boundaries of the matrix inhibits the diffusion of Cr ions, resulting in the inability to form an effective protective layer of Cr2O3 oxidation on the surface.

The Effect of Zr on the High‐Temperature Oxidation Resistance of 12Cr Ferritic/Martensitic Steels

The high‐temperature oxidation resistance of 12Cr ferritic/martensitic steels with Zr contents in the range of 0–1.3607 wt% is investigated at 650 and 800 °C in air. The results show that the oxidation resistance of steels is improved by adding Zr. The oxide layer on the surface of steels after oxidation is mainly composed of MnCr2O4 and Cr2O3, where traces of Mn2O3 and ZrO2 oxides can also be detected there. The oxide layer of steels consists of two layers, that is, the outer Mn‐rich oxides (MnCr2O4, Mn2O3) and the inner Cr‐rich oxides (Cr2O3). For none‐Zr steels oxidized at 650 °C, Cr2O3 oxides are also formed in the outer layer. The addition of Zr promotes the outer oxides to change from Cr2O3 oxides to MnCr2O4 oxides and reduces the growth rate of MnCr2O4 oxides. The effect of Zr on the high‐temperature oxidation resistance of steels can be attributed to its promoting effect on the formation of outer Mn‐rich oxides, which can refine the size of outer Mn‐rich oxides and form a dense outer oxide layer. The dense outer oxide layer can inhibit the inward diffusion of oxygen and improve the oxidation resistance of steel.

Oxidation Behavior of AISI 316 Steel Coated with Ni-P-TiO2-Al2O3 Composite Coating

Austenitic steels have numerous applications in high-temperature environments. The thermally-grown chromia scale on the steel surface may be-come unstable at high temperatures and as a result, oxidation resistance of steel will decrease. A potentially method for improving oxidation properties is the use of composite coatings using techniques such as electroplating. In the present study, Ni-P-TiO2-Al2O3 composite coating was deposited on AISI 316 steel sub-strate by electroplating. The as-coated samples were examined with scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). X-Ray diffraction (XRD) was also used to identify the formed phases in the as-coated structures. In order to evaluate oxidation behavior, isothermal oxidation and cy-clic oxidation were conducted at 800 oC. Isothermal oxidation of uncoated steels revealed higher weight gain in comparison with Ni-P-TiO2-Al2O3 composite-coated samples. The coating layer limited the outward diffusion of Cr cation and the inward diffusion of oxygen anion and resulted in better oxidation resistance. According to the results of cyclic oxidation, coated substrates demonstrated excel-lent resistance against spallation and cracking.

THE INFLUENCE OF ARSENIC ON THE RESISTANCE OF LOW-CARBON AND LOW-ALLOYED STEELS AGAINST ATMOSPHERIC CORROSION. PART 1

The analysis of bibliographic data about the influence of arsenic on corrosion resistance of low-carbon low-alloyed steels has been carried out. The authors have revealed the reasons and proposed the mechanism which explains the influence of arsenic on oxidation resistance of steels, their stability against the oxidization in the conditions of atmospheric corrosion and in sea water.

ICOPE-15-C107 Effect of surface machine on the oxidation resistance of steels with different Cr content in steam at high temperature

ICOPE-15-C107 Effect of surface machine on the oxidation resistance of steels with different Cr content in steam at high temperature

Control of Aluminum Concentration on Iron Surface by Powder Eutectic Coating Using Laser-Heating

The addition of large amounts of chrome and nickel is employed to increase the oxidation and corrosion resistance of steels. Zinc or tin coating is often used for low-alloyed steels; however, the use of such elements can cause environmental problems. Some alloying elements, such as nickel and copper, are detrimental to recycling processes, due to the difficulty of removal when scrap steel is melted. Therefore, it is important to improve the corrosion and oxidation resistance of steels without the use of these elements. Aluminizing is considered to be an attractive alternative treatment in this respect. Aluminized steels are beneficial in the steel making process when they constitute part of the steel scrap, because aluminum acts as scavengers for oxygen in molten steel. A new powder liquid-coating method is proposed for the aluminization of iron.1) Phase estimation during coating process and oxidation resistance of coated layer were discussed in the previous paper.2,3) The aim of this study is control of the surface aluminum concentration in the coated layer.

Effect of Shot Peening on the Oxidation Resistance of TP304H and HR3C Steels in Water Vapor

Oxidation behaviors of TP304H and HR3C steels with and without shot peening were investigated at 650 °C in water vapor. The oxide scales were studied with XRD, SEM and EDX. The results showed that the oxidation resistance of the steels was effectively improved by shot peening, especially for TP304H. The oxidation resistance of shot peened TP304H was even better than shot peened HR3C. The shot peening process produced an ultra-fine surface microstructure and plenty of slip bands which resulted in an enhanced Cr diffusivity to form Cr-rich oxides. The shot-peening process also induced martensite at the surface, which enhanced Cr diffusion and significantly affected the oxidation behavior of the TP304H steel.

Influence of the surface mechanical pulsed treatment on the oxidation of Fe – 0.2C – 13Cr – 0.3Si steel in lead melts

We study the influence of mechanical pulsed treatment (MPT-1) on the corrosion resistance of Fe – 0.2C – 13Cr – 0.3Si steel in a lead melt containing 1.3 ⋅ 10 – 3 wt.% of oxygen at a temperature of 550°C for 1000 h. It is shown that the MPT promotes the formation of micro- and macrodefects in the subsurface zone of the specimens, which intensifies the process of oxidation of steel. The oxidation resistance of steel after MPT-2 and MPT-3 (with adding aluminum and silicon) is attained as a result of the formation of a hardened zone with nanocrystalline structure and large lengths of grain boundaries intensifying the diffusion of chromium into the oxide films.

Influence of high pressure normalizing heat treatment on microstructure and creep strength of high Cr steels

Abstract Chromium is an effective element for improvement in the oxidation resistance of steels. However, chromium addition to ferritic creep resistant steel is restricted to around 9–10 wt.%, since excess addition of chromium results in formation of delta-ferrite which decreases creep strength and toughness. In this study, influence of normalizing heat treatment under high pressure on microstructure and creep strength has been investigated in a steel containing 15 wt.% of chromium, since austenite single phase region is extended up to about 20 wt.% of chromium under high pressure of about 4 GPa. In contrast to a ferritic microstructure of the steel normalized under atmospheric pressure of 100 kPa, the martensitic one was found in steel normalized under high pressure of 4 GPa. Hardness in the as tempered condition of the steels subjected to normalizing heat treatment at 1273 and 1173 K under 4 GPa was 290 and 289 HV, respectively. This is significantly higher than the value of 182 HV for the steel normalized at 1273 K under atmospheric pressure of 100 kPa. Creep rate of the steel normalized under high pressure of 4 GPa was significantly smaller than that of the steel normalized under pressure of 100 kPa. It has been concluded that high pressure normalizing heat treatment is effective to suppress a formation of delta-ferrite and to improve both creep strength and oxidation resistance.

Applications of soft X-ray absorption spectroscopy to the study of passive and oxide layers on stainless steels: influence of ion implantation

Abstract Soft X-ray absorption spectroscopy (XAS) has been used to study the influence of Si ion implantation on the passive layer of AISI 304 stainless steel, as well as on its high-temperature oxidation behaviour. Ion implantation is a usual technique to improve the corrosion and oxidation resistance of steels. To study the effects of ion implantation on the room temperature corrosion behavior of AISI 304 stainless steel, XAS was performed on the passive layer formed spontaneously in contact with air. To analyse the effects of ion implantation at high temperatures, the oxide layer formed after an isothermal oxidation at 900°C for 32 h was also studied. The results show a positive influence of Si ion implantation on the corrosion behaviour of AISI 304 stainless steel. XAS in the soft X-ray excitation mode has proved to be a very suitable technique to perform corrosion science studies.

Effect of Chlorine and of H2S on the Oxidation Resistance of Various Austenitic Stainless Steels

AbstractStudies were made on the oxidation resistance of austenitic stainless steels type AISI 304, 320, 316, and 321 in humid oxygen at 30 torr (4 kN/m2) at 950°c and at 650°c,for 250 h infive 50 h cycles, and also on the effect of intermittent exposure of the specimens to Cl2 or to H2S during theoxidation experiment. In addition, the oxidation resistance of these steels in (95% O2 + 5% Cl2), (90%O2 + 10%H2S),and (85% O2 + 5% Cl2 + 10H2S) was also studied. Intermittent exposure to Cl2 or to H2S damaged the protective oxide layersand increased the rate of oxidation. Attack in (95% O2 + 5% Cl2 at 950°c was found to be extremely severe and the test had to be terminated after a short period; however, oxidation in (90% O2 + 10% H2S) at 950°c drastically reduced the rates for all the steels. Tests in (85% O2 + 5% Cl2 + 10% H2S) at 950°c exhibited an intermediate type of attack. Oxidation rates of various steels in wet O2 at 650°c were much lower than those at 950°c, and the intermittent exposure to Cl2 or to H...

Siliciding of steel in mixtures of silicon with silicon dioxide

Siliciding in a mixture of Si+SiO2 in hydrogen at 1050–1230°C increases the oxidation resistance of steel in air at temperatures of 850–950°C.

The structure of oxide films and scaling resistance of pearlite steel, and their dependence on alloying

1. The structure of oxide films and the resistance of pearlitic steel to scaling at 600°C in ambient air atmosphere depends on the degree of alloying. 2. An increase in the concentration of the alloying elements causes the oxidation resistance of steel in the air medium to rise at 600°C. The best results were obtained for steel with 7% Cr: the magnitude of weight increase is 0.3 mg/cm2 after 1000-hours oxidizing heating at 600°C. A single-phase oxide film (oxide of the α-Fe2O3 typed) was observable on the surface of the metal. The lowest increase in oxidation resistance was registered for steel alloyed with cobalt. After prolonged oxidizing, along with α-Fe2O3 and Fe3O4, FeO wustite was also revealed in the oxide film of steels alloyed by cobalt. 3. It is recommended to conduct electron diffraction studies at the early stages of the steel oxidizing process at 300–600°C (with holding times amounting to 1 hour). Additional alloying of pearlitic steel with chrome, silicon, aluminum, cobalt, tungsten, and boron raises the temperature at which the second phase (Fe3O4) appears in the oxide film. A rise of the above temperature depends on the type and the concentration of the alloying element. The steels for which the highest temperature was observed during the transition of the oxide film from a single- to two-phase state possess the highest resistance to scaling at 600°C.