Effect of Si on High-Temperature Oxidation of Steel during Hot Rolling

2008 ◽  
Vol 273-276 ◽  
pp. 655-660 ◽  
Author(s):  
Lucia Suarez ◽  
Juergen Schneider ◽  
Yvan Houbaert
Keyword(s):  
High Temperature ◽  
Hot Rolling ◽  
High Temperature Oxidation ◽  
Surface Defects ◽  
Steel Strip ◽  
Surface Oxidation ◽  
Strip Surface ◽  
Temperature Oxidation ◽  
Scale Properties ◽  
Specific Oxidation

An oxide scale layer always forms at the strip surface during the hot rolling process. As a consequence, de-scaling and pickling operations must be performed prior or after hot rolling. Many surface defects caused by hot rolling are related to oxidation in the reheating furnace. One of these is the melting of eutectic FeO/Fe2SiO4 during reheating over 1170°C giving as a result red scale defects in Si-added steel. On the other hand, steel strip surface oxidation during hot rolling causes an industrial and environmental problem: secondary oxide is removed after roughing, but tertiary oxide scales already start to form before entering the finishing stands. Their properties affect the final steel surface quality and its response to further processing. Furthermore, the addition of alloying elements has an important impact on scale properties. In particular the alloying of silicon effects the region between scale and substrate. It causes peculiar surface properties inherited from its specific oxidation characteristics. Conventional oxidation experiments in air of silicon steels are a valuable tool to study the influence of Si on steel oxidation. After oxidation in air in the temperature range of 900-1250°C it has been observed that Si enhance markedly scale adhesion, especially above 1177°C (the eutectic temperature of FeO-Fe2SiO4 ) and also at lower temperatures. Special attention has been paid on the investigation of the effects of alloying Si on the high-temperature oxidation of steel, for a better understanding of the behaviour of modern steels during hot rolling.

Carbide Fragmentation and Dissolution in a High-Carbon High-Chromium Steel Using Hot Rolling Process: Microstructure Evolution, Wear, High-Temperature Oxidation, and Chloride-Induced Corrosion Properties

CORROSION ◽  
10.5006/2749 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 958-970 ◽  
Author(s):  
Majid Shahsanaei ◽  
Sadegh Pour-Ali ◽  
Ali-Reza Kiani-Rashid ◽  
Sannakaisa Virtanen
Keyword(s):  
High Temperature ◽  
Corrosion Behavior ◽  
Hot Rolling ◽  
High Temperature Oxidation ◽  
Rolling Process ◽  
High Carbon ◽  
Corrosion Properties ◽  
Temperature Oxidation ◽  
High Chromium ◽  
Hot Rolling Process

A series of hot rolling processes with different reduction percentages (10%, 30%, and 50%) were applied to a high-carbon high-chromium tool steel (2HCTS). Microstructural evolutions, wear behavior, high-temperature oxidation, and aqueous corrosion properties were investigated. The results revealed the breakage and dissolution of primary carbides and a uniform carbide distribution after the hot rolling process. It was proposed that the presence of higher amounts of dissolved chromium in the hot rolled samples leads to the formation of Cr-rich oxides with more protection and less porosity at high temperatures, as well as an improved corrosion behavior in 3.5 wt% NaCl solution. This improvement in the corrosion behavior is not at the expense of the degradation of wear resistance. Probable mechanisms for carbides dissolution are also discussed.

High-Temperature Oxidation Behaviors of 30Cr25Ni20Si Heat-Resistant Steel in Air

2020 ◽  
Vol 861 ◽  
pp. 83-88
Author(s):  
You Yang ◽  
Xiao Dong Wang
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperature Oxidation ◽  
Film Growth ◽  
Surface Oxidation ◽  
Mass Gain ◽  
Resistant Steel ◽  
Temperature Oxidation ◽  
Heat Resistant Steel ◽  
Heat Resistant

High temperature oxidation dynamic behaviors and mechanisms for 30Cr25Ni20Si heat-resistant steel were investigated at 800, 900 and 1000°C. The oxide layers were characterized by scanning electron microscopy (SEM-EDS), X-ray diffractometer (XRD). The results showed that the oxidation rate of test alloys is increased with increasing the oxidation time. The oxidation dynamic curves at 800 and 900°C follow from liner to parabolic oxidation law. The transition point is 10 h. At 1000°C, the steel exhibits a catastrophic oxidation, and the oxidation mass gain value at 50 h is 0.77 mg/cm2. This suggests that the steel at 900°C has formed a dense protective surface oxidation film, effectively preventing the diffusion of the oxygen atoms and other corrosive gas into the alloy. Therefore, at the first stage of oxidation, chemical adsorption and reaction determine the oxide film composition and formation process. At the oxide film growth stage, oxidation is controlled by migration of ions or electrons across the oxide film. When the spinel scale forms, it acts as a compact barrier for O element and improving the oxidation resistance.

scholarly journals High-Temperature Oxidation Performance of 4Cr4Mo2NiMnSiV Hot Die Steel

2021 ◽  
Author(s):  
Renheng HAN ◽  
Ning LI ◽  
Ziming BAO ◽  
Xinjian HU ◽  
Hexin ZHANG ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
High Temperature Oxidation ◽  
Metallic Matrix ◽  
Oxidation Mechanism ◽  
Surface Oxidation ◽  
Ambient Atmosphere ◽  
Temperature Oxidation ◽  
Die Steel ◽  
Hot Working Die Steel

A new type of hot working die steel was designed by using JMatPro, and high-temperature oxidation tests were carried out in the ambient atmosphere at 600 ℃ and 700 ℃. The heat treatment process and oxidation mechanism of the designed 4Cr4Mo2NiMnSiV steel were studied in detail. XRD, SEM and EDS were used to analyze the crystallographic phases, surface and cross-section morphologies of the oxide films. The results show that the main phases in the 4Cr4Mo2NiMnSiV steel were γ and α + δ. During the high-temperature oxidation, oxidation of the Fe outer layer and Cr inner layer occurred. After oxidation at 600℃, the surface oxidation layer comprised a monolayer with an uneven morphology. The surface oxide film had two layers after oxidation at 700℃. The outer oxide layer mainly contained Fe2O3 and Fe3O4, while the inner oxide layer mainly contained Cr2O3. The microstructure was relatively regular and had a significant effect on the protection of the metallic matrix. When oxidized, the 4Cr4Mo2NiMnSiV alloy steel easily formed protective layers, such as Cr2O3 and SiO2, so that the test steel had excellent oxidation resistance at high temperatures.

Effect of the Surface Oxidation on the Hot-Dip Zinc Galvanizing of Cast Iron

2011 ◽  
Vol 56 (3) ◽  
pp. 839-849 ◽  
Author(s):  
D. Jędrzejczyk ◽  
M. Hajduga
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Layer Structure ◽  
Subsurface Layer ◽  
Zinc Coating ◽  
Surface Oxidation ◽  
Profile Measurement ◽  
Temperature Oxidation

Effect of the Surface Oxidation on the Hot-Dip Zinc Galvanizing of Cast Iron In presented work authors analyzed the high-temperature oxidation process from the point of view of its influence on effects obtained during cast iron hot-dip zinc coating. Research concerned the influence of the high-temperature oxidation, as a preliminary stage previous to coating with zinc on the change of surface layer structure as well as subsurface layer of cast iron with flake, vermicular and nodular graphite. To obtain proper results of Zn coating the special chemical etching of cast iron after oxidation is necessary. The effects were compared to these obtained during cast iron coating without preliminary thermal processing. To comparative analysis both optical and scanning microscope, RTG measurement and profile measurement gauge results were applied. As a consequence of conducted high-temperature oxidation in subsurface layer of cast iron pores have been created, that in result of coating in liquid zinc were filled with new phase and in this way the new zone with different properties was obtained. It was additionally stated that the cast iron layer enriched in zinc is considerably thicker than layers got with application of other methods. Thickness of sub-surface layer where "after-graphite" pores are filled with zinc depends directly on the kind of graphite. When the flake and vermicular/compacted graphite is observed depth of penetration reaches 120 μm, whereas in nodular cast iron it reaches only 15μm, although sometimes single voids filled with zinc are observed at 75μm depth.

scholarly journals High Temperature Oxidation of Ultra-Low-Carbon Steel

2006 ◽  
Vol 258-260 ◽  
pp. 158-163 ◽  
Author(s):  
Lucia Suarez ◽  
R. Coto ◽  
X. Vanden Eynde ◽  
M. Lamberigts ◽  
Yvan Houbaert
Keyword(s):  
High Temperature ◽  
Carbon Steel ◽  
High Temperature Oxidation ◽  
Low Carbon Steel ◽  
Controlled Atmosphere ◽  
Low Carbon ◽  
Strip Surface ◽  
Temperature Oxidation ◽  
Scale Thickness ◽  
Ultra Low Carbon Steel

An oxide scale layer always forms at the strip surface during the hot rolling process. Its properties have a large impact on surface quality. The most important features of the oxide layer are its thickness, composition, structure, adherence and coherence. Temperature, time and gas atmosphere determine the growth of oxide layers. In this paper, the high temperature oxidation properties of ultra low carbon steels are discussed in terms of oxide growth mechanism, kinetics and phase morphology. The oxidation kinetics of ultra-low carbon steel (ULC) in air, its scale structure and composition were investigated over the temperature range 923-1473K. Oxidation experiments were performed either under controlled atmosphere or in air, to analyse the oxidation process during strip production. A first series of experiments was carried out in an electric furnace at temperatures ranging from 923 to 1473K, for times between 16 and 7200s. A second series was carried out in a device especially designed to control the atmosphere. After heating under pure nitrogen, the samples were oxidised in air at temperatures between 923-1323K for various oxidation times. Thus treated specimens were characterised by metallography and their scale thickness was measured under the optical microscope. Scale morphology was studied and scale composition confirmed by EDS (Energy Dispersive Spectroscopy) and EBSD (Electron Backscattered Diffraction) analysis. Results show that scale growth under controlled atmosphere is significantly faster than under non controlled conditions, additionally the adherence of the scale formed in the laboratory device was significantly better than the other one. It is clear that scale thickness and constitution depend strongly on the oxidation potential of atmosphere. Computed parabolic activation energies (Ea) values are in good agreement with those found in the literature.

Suppression of Surface Hot Shortness Caused by Copper during Hot Rolling

2011 ◽  
Vol 696 ◽  
pp. 183-188
Author(s):  
Yasumitsu Kondo
Keyword(s):  
High Temperature ◽  
Hot Rolling ◽  
Copper Content ◽  
High Temperature Oxidation ◽  
Tensile Tests ◽  
Temperature Oxidation ◽  
Magnetite Layer ◽  
Hot Shortness ◽  
Copper Distribution ◽  
Surface Hot Shortness

Since copper content in steel causes hot shortness, it is important to understand copper behaviour during high-temperature oxidation, in order to control the precipitated copper. This study examines copper distribution during the oxidation of steel. From the oxidation tests, it is shown that precipitated copper existing in the scale/steel interface is absorbed into the magnetite layer or evaporates into the atmosphere. Then, a proposed method to suppress hot shortness is tested by oxidation-tensile tests at high temperature and is proven to be effective.

Sign in / Sign up

Export Citation Format

Share Document