Variations in microstructure of high chromium cast irons and resultant changes in resistance to wear, corrosion and corrosive wear

Tang, Xiaodong; Chung, R.J.; Li, D.Y.; Hinckley, B.; Dolman, Kevin

doi:10.1016/j.wear.2008.11.025

Cited by 98 publications

(40 citation statements)

References 15 publications

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“…As the Cr/C ratio increases, the difference between the Cr content in the eutectic carbide and that of in the matrix, described as Cr partition ratio in Table 2, decreased from 4.19 for the HCCI-3 alloy to 4.09 and 3.45 for the HCCI-2 and HCCI-1 alloys, respectively. The observed reduction in corrosion current density with increasing Cr/C ratio is in an agreement with the findings of the previous studies [4,9,26].…”

Section: The Relationship Between the Microstructure And Corrosion Besupporting

confidence: 92%

Wear and Corrosion Behavior of High-Cr White Cast Iron Alloys in Different Corrosive Media

et al. 2015

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This study aims to investigate the effect of Cr/ C ratio on wear and corrosion behavior of a group of highCr white cast iron (HCCI) alloys. Three different alloys of HCCI with different chemical compositions were tested against 3.5 % NaCl, 0.5 M H 2 SO 4 , and 0.5 M NaOH solutions as corrosive media. Electrochemical polarization technique has been used to determine the corrosion current density. The microstructure characteristics of HCCI alloys were analyzed by using optical microscope, SEM, EDS, and XRD. XRD analysis reveals that the microstructure of the HCCI alloys is composed of a network of chromiumrich carbides (M 7 C 3 ) in an austenitic matrix. The abrasive wear resistance of HCCI alloys was found to be rely on their chemical composition and microstructure. The corrosion resistance of the HCCI alloys strongly depends on the Cr/C ratio and the ratio of chromium content in the M 7 C 3 carbide to that in the matrix (CrM 7 C 3 /Matrix). The experimental results of this study showed that the alloy HCCI-2 with the lower Cr/C ratio exhibited the lowest abrasive wear loss while the alloy HCCI-1 with higher Cr/ C ratio exhibited the highest abrasive wear loss. On the other hand, the HCCI-1 alloy was the most corrosion resistant and revealed the lowest current density. In addition, the corrosion current density of all specimens is elevated in 0.5 M H 2 SO 4 solution in comparison with 3.5 wt% NaCl and 0.5 M NaOH solutions.

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Section: The Relationship Between the Microstructure And Corrosion Besupporting

confidence: 92%

Wear and Corrosion Behavior of High-Cr White Cast Iron Alloys in Different Corrosive Media

et al. 2015

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“…Recent advances in the foundry technology have made it possible to cast hypereutectic white cast irons with higher carbon and chromium contents [4]. In our previous studies, HCCIs containing 35 wt%Cr and 45 wt%Cr were fabricated and preliminarily studied, which demonstrated excellent performance against wear and corrosion [7,8].…”

Section: Introductionmentioning

confidence: 99%

Beneficial Effects of the Core–Shell Structure of Primary Carbides in High-Cr (45 wt%) White Cast Irons on Their Mechanical Behavior and Wear Resistance

Tang

Hinckley³

et al. 2015

Tribol Lett

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High-chromium cast irons (HCCIs) are widely used in many industrial processes involving wear and corrosion, such as oil sands mining and slurry handling in the oil sands industry. In very harsh mining environment and severe working conditions, conventional HCCIs, however, often exhibit a short service life. Great efforts have been made to improve the performance of HCCIs. One of the trials is to extend the chromium content to a higher level, e.g., 45 wt%, and widen the carbon content to a range of 1-6 wt%. In this study, we investigated the wear behavior of 45-series (Fe-45 wt%Cr with 1-6 wt%C) and observed that 45-4 HCCI (Fe-45 wt%Cr-4 wt%C) had the highest hardness and exhibited remarkably high resistance to abrasion and erosion. Microstructure analysis showed that the primary carbides in 45-4 had a core-shell structure. The outer shell was M 23 C 6 , while the inner core was harder M 7 C 3 , confirmed by the EBSD technique. The ferrous matrix was eutectic colony with martensite and fine M 23 C 6 carbides. Micro-mechanical probing in combination with finite element analysis demonstrated that the core-shell structure helped reduce the interfacial stress, thus enhancing the hardness and overall wear resistance of the material.

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“…Tang et al [9,10] found that in acidic solution of 0.5 M H 2 SO 4 , the corrosion rate decreased with increasing percentage of carbon which resulted in HCWI to form more chromium carbides which decreases the volume fraction of austenite matrix. The higher carbon content increased the area ratio of cathode chromium carbides to anode eutectic austenite matrix in acidic environment.…”

Section: Introductionmentioning

confidence: 99%

Corrosion Behaviour of High Chromium White Iron Hardfacing Alloys in Acidic and Neutral Solutions

Marimuthu

Kannoorpatti

2016

J Bio Tribo Corros

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Hardfacing alloys of High Chromium White Irons (HCWI) were deposited on low carbon steel using Shielded Metal Arc Welding. Microstructure of HCWI consists of primary carbides, eutectic carbides and eutectic austenitic/martensitic matrix. This study investigated the corrosion behaviour of HCWI in both acid and neutral solutions. The corrosion behaviour of HCWI was evaluated using anodic polarisation technique. It was found that in acid solution at pH 1.5, corrosion occurs on eutectic austenite/martensitic matrix whereas at pH 2, the corrosion occurs on eutectic carbides. In the neutral environment at pH 7, corrosion of HCWI occurred in the eutectic austenite/martensite matrix in the presence of chloride ions, while in the buffered solution, corrosion occurred in the carbides. The results of this study show that the corrosion mechanism of HCWI for both acid and neutral environments was due to potential difference between carbides and eutectic austenite/martensitic matrix. The superimposed Pourbaix diagrams of chromium carbides with iron (Fe) and niobium carbide were useful in explaining the behaviour of HCWI in both acid and neutral solutions.

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Variations in microstructure of high chromium cast irons and resultant changes in resistance to wear, corrosion and corrosive wear

Cited by 98 publications

References 15 publications

Wear and Corrosion Behavior of High-Cr White Cast Iron Alloys in Different Corrosive Media

Wear and Corrosion Behavior of High-Cr White Cast Iron Alloys in Different Corrosive Media

Beneficial Effects of the Core–Shell Structure of Primary Carbides in High-Cr (45 wt%) White Cast Irons on Their Mechanical Behavior and Wear Resistance

Corrosion Behaviour of High Chromium White Iron Hardfacing Alloys in Acidic and Neutral Solutions

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