The influence of titanium addition on wettability of high-chromium white cast iron-matrix composites

2018 ◽  
Vol 53 (11) ◽  
pp. 1567-1576 ◽  
Author(s):  
Takalani Madzivhandila ◽  
Shepherd Bhero ◽  
Farouk Varachia

The mining industry exerts ever increasing demand for components with high wear resistance to the extent that plain ferrous alloys are falling short. Innovative metal-matrix composites non-ferrous metals have been widely researched and used. Casting composites based on ferrous alloys pose monumental challenges in casting. First, the density differential results in large buoyant forces on the ceramic such that unless a rigid structure is configured, the less dense ceramic floats on the metal stream. Second, the poor wetting properties between metal and ceramic will result in inferior bonding of the matrix, hence separation of solids in service. The paper attempts to improve the bonding characteristics of zirconia and alumina through wettability studies. High-chromium white cast iron was used as a substrate. The wetting behavior of molten iron on the substrates of zirconia and alumina was investigated. The study shows that alumina is poorly wetted with copper and nickel; the wetting angles were higher than 90°. Thus, the envisaged coating of alumina with copper or nickel prior to casting of ferrous melts will not significantly alter or improve wettability of alumina. Between copper and nickel, nickel has better bonding with alumina than copper. Titanium in high-chromium white cast iron was found to improve the wetting characteristics on alumina. The wetting angle decreased with increased titanium content.

2016 ◽  
Vol 25 (41) ◽  
pp. 93 ◽  
Author(s):  
Oscar Fabián Higuera-Cobos ◽  
Florina-Diana Dumitru ◽  
Dairo Hernán Mesa-Grajales

<p>High-Chromium White Cast Iron is a material highly used in mining and drilling shafts for oil extraction, due to its high wear resistance. However, because of the austenitic matrix found in the as-cast state, an adequate heat treatment cycle is necessary. This paper studies the effects of different cooling media after a destabilization treatment on the microstructure, hardening and abrasion resistance behaviors of a hypoeutectic high chromium white cast iron. The results show that although air cooling followed by immersion in CO2 can effectively reduce the retained austenite, this is not enough to transform completely the retained austenite into martensite. The low retained austenite percentages improve bulk hardness, but they decrease the abrasion resistance of the high chromium cast iron. The best combination of hardness and wear resistance was found in the samples cooled in air, due to the percentage of retained austenite and a moderate precipitation of chromium carbide.</p>


Tribology ◽  
2005 ◽  
Author(s):  
I. Hilerio ◽  
M. A. Barron

Presence oxides on sliding surfaces can greatly influence friction and wear. Oxides have been usually considered as a friction and wear reducing agent acting as a solid lubricant. Effects of pre-oxidation, carried out at different temperatures, on the tribological behaviour of a high-speed steel and a high chromium white cast iron sliding against a ceramic material have been studied in this work. Wear was evaluated through a new methodology, which calculates the volume of removed material from topography data of the worn surface. Wear mechanisms were determined by scanning electron microscopy analysis. Results showed a large difference between wear rate of the studied materials. High speed steel had a much lower wear than high chromium white cast iron. However pre-oxidation did not cause any meaningful influence on the tribological behaviour of both material, at least in the conditions evaluated in this work.


2022 ◽  
Vol 275 ◽  
pp. 125232
Author(s):  
Riki Hendra Purba ◽  
Kazumichi Shimizu ◽  
Kenta Kusumoto ◽  
Yila Gaqi ◽  
Takayuki Todaka

2018 ◽  
Vol 70 (4) ◽  
pp. 628-638 ◽  
Author(s):  
Mohammed Ahmed Al-Bukhaiti ◽  
Ahmed Abouel Kasem Mohamad ◽  
Karam Mosa Emara ◽  
Shemy M. Ahmed

Purpose This paper aims to investigate the influence of slurry concentration on the erosion behavior of AISI 5117 steel and high-chromium white cast iron by using a whirling-arm rig. In this study, the slurry erosion mechanism with particle concentration has been studied. Design/methodology/approach The tests were carried out with particle concentrations in the range of 1-7 Wt.%, and the impact velocity of slurry stream was 15 m/s. Silica sand with a nominal size range of 500-710 µm was used as an erodent. The study revealed that the failure mode was independent of concentration. Findings The results showed that the erosion rate decreases with the increase in particle concentration and the variation in the reduction depends on the material. It was found that the variation of fractal dimension calculated from slope of linearized power spectral density of eroded surface image for different concentrations can be used to characterize the slurry erosion intensity in a similar manner to the erosion rate. It was also found that the variation of fractal dimension versus concentration of sand has a general trend that does not depend on magnification factor. Originality/value Using the gravitational measurement and image analysis, the variation of the wear with slurry concentration has been analyzed to investigate the implicated mechanisms of erosion during the process.


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