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.

Research on high-temperature oxidation resistance, hot forming ability, and microstructure of Al–Si–Cu coating for 22MnB5 steel

2021 ◽  
Vol 40 (1) ◽  
pp. 397-409
Author(s):  
Ziliu Xiong ◽  
Zhangguo Lin ◽  
Jianjun Qi ◽  
Li Sun ◽  
Guangxin Wu ◽  
...  
Keyword(s):  
Surface Layer ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Hot Stamping ◽  
Optical Microscope ◽  
Hot Forming ◽  
Metal Compound ◽  
Temperature Oxidation ◽  
Substrate Steel

Abstract High-temperature oxidation resistance, hot formability, element distribution, and microstructure of Al-10% Si-(0.5–3.0%)Cu coating were investigated by means of glow discharge spectroscopy, optical microscope, scanning electron microscope, and energy-dispersive spectroscopy. Results show that the addition of Cu can increase high-temperature oxidation resistance above 950°C and improve hot formability so that no crack spreads into substrate steel as hot forming at 33.3% strain. Oxidation film structure is continual and compacting, and Si highly concentrates in the surface layer. The distribution of Cu has skin effect with peaking content 8.2% in the surface layer. After hot stamping, Al and Si diffuse into substrate steel, and Cu diffuses from inner to outer coating. Al–Si–Cu coating has smoother surface, straighter diffusion layer, and finer metal compound than Al–Si coating. Surface and diffusion layers are identified as aluminum oxide, Si-rich, and Cu phase and Al7SiFe2, Al3Fe, and CuAl3, respectively. Al-rich phase and the metal compound are composed of α-Al dissolving Fe, Si, and Cu and Al–Si matrix, Cu3Al, respectively.

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.

Effects of Aluminizing on the High Temperature Oxidation Behavior of High Silicon Cast Iron

2009 ◽  
Vol 79-82 ◽  
pp. 2151-2154
Author(s):  
Meng Bin Lin ◽  
Chaur Jeng Wang
Keyword(s):  
Cast Iron ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
X Ray ◽  
Oxygen Penetration ◽  
Coating Layers ◽  
High Silicon ◽  
High Temperature Oxidation Behavior

In this study, the aluminizing of high silicon cast iron by hot-dipping in pure Al melt was performed and their high temperature oxidation behaviour was tested at 750 °C for virous exposure time. After high temperature oxidation tests, the microstructure analysis of all samples were investigated by means of metallographical examination, scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectrometer (EDS) and X-ray diffractometry (XRD).The results showed that the coating layers consisted of three layer, in the sequence of Al, Fe-Al and Si-rich layers from external topcoat to substrate. Nodules graphite had a blocking effect to retard the outward diffusion of Fe atoms and impeded the growth of Fe2Al5 in C-axis. Eventually, the cast iron substrate was oxidized directly by oxygen penetration via the greater cracks and pores to form Fe oxide nodules after 750 °C oxidation for 48h.

scholarly journals The casting process and high temperature oxidation resistance of high chromium cast iron grate bar

2019 ◽  
Vol 39 (1) ◽  
pp. 29-36
Author(s):  
Chen Zhiru ◽  
Xu Lei ◽  
Zhao Linwei ◽  
Wang Youchao ◽  
Li Changyun ◽  
...  
Keyword(s):  
Cast Iron ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Casting Process ◽  
Shrinkage Cavity ◽  
Temperature Oxidation ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Chromium Cast Iron

The solidification process of a high chromium cast iron grate bar used for sinter machine was simulated, and high temperature oxidation resistance was also investigated. The simulation result shows that sequence solidification can be achieved and no shrinkage cavity and porosity were observed. Based on the analysis of the microstructure, it could be known that the grate bar was well protected by the Fe3O4、Fe2O3 and Cr2O3 oxide films at temperatures lower than 800°C.

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