scholarly journals Bifilm Defects in Ti-Inoculated Chromium White Cast Iron

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3124
Author(s):  
Malwina Dojka ◽  
Marcin Stawarz

In recent years, white chromium cast iron has gained a well-settled position among wear-resistant materials. In recent times, chromium cast iron samples containing titanium have attracted attention. In cast iron samples, titanium combines with carbon and forms TiC particles, which may be form a crystallization underlay for eutectic M7C3 carbides and austenite. Accordingly, the inoculation process occurring in the crystallizing alloy should result in the proper, regular distribution of fine eutectic chromium carbides in the austenitic matrix. The presented research was conducted on 20% Cr hypoeutectic white cast iron with the addition of 0.5, 1, and 2% of Ti. Ti inoculation and the presence of TiC allowed for superior wear properties to be obtained. However, the conducted study revealed a significant decrease in the impact strength of examined alloys, especially for the cast iron samples with a high amount of Ti, in which the TiC compounds agglomerated. Titanium compounds accumulate in clusters and their distribution is irregular. Most of the TiC compounds were transported by the crystallization front into the center of the castings, where micropores were formed, meaning they were no longer effective crystallization underlays. In the authors’ opinion, the agglomerate formation is strictly connected with the appearance of bifilm defects in the casting microstructure. The conducted research shows how an incorrect volume of an additive may have negative influences on the properties of the casting. This is a vital issue not only from a technological point of view, but also for economic reasons.

2016 ◽  
Vol 16 (2) ◽  
pp. 89-94 ◽  
Author(s):  
E. Olejnik ◽  
Ł. Szymański ◽  
P. Kurtyka ◽  
T. Tokarski ◽  
B. Grabowska ◽  
...  

Abstract In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.


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.


2020 ◽  
Vol 46 (3) ◽  
pp. 2592-2601
Author(s):  
Tian-xing Huang ◽  
Zhuan Li ◽  
Yan-qi Huang ◽  
Yang Li ◽  
Peng Xiao

2011 ◽  
Vol 695 ◽  
pp. 397-400
Author(s):  
Ru Qing Huang ◽  
Ri Lai Ma ◽  
Zhen Lin Lu ◽  
Yan Zhang

The effect of alloying elements on the corrosion wear behaviors of low chromium cast iron in slurry with different ions was studied by self-made three-body corrosion wear tester. The results show that the corrosion wear resistance of low chromium cast iron was decreased with the increase of concentration of Cu2+ ion or SO42- ion in slurry. The corrosion wear mechanism of low chromium cast iron was dominated by micro-cutting of abrasive, accompanying by corrosion action. The addition of alloying elements did not improve the corrosion wear properties of low chromium cast iron obviously, because the amount of carbide and its hardness was decreased when the alloying elements were added into low chromium cast iron as well as the amount of silicon element was increased.


Author(s):  
Julieta Kaleicheva ◽  
Krasimir Kirov ◽  
Valentin Plamenov Mishev ◽  
Zdravka Karaguiozova

The microstructure and mechanical properties of high chromium white cast iron with composition: 2,6÷3,4% C; 0,9÷1,1% Si; 0,8÷1,1% Mn; 1,0÷1,3% Mo; 12,3÷13,4% Cr, additionally doped with boron in an amount of 0,18% to 1,25% is investigated. The microstructure of six compositions of white cast irons is studied by means of an optical metallographic analysis - one without boron, and the others contain 0,18%; 0,23%; 0,59%; 0,96% and 1,25% boron. A test is performed to determine: hardness by the Rockwell method; microhardness; bending strength and impact toughness. It was found that at a boron content of 0,18%; 0,23% and 0,59%, the structure of white cast irons is subeutectic, with impact toughness in the range of 1,80÷1,52 J/cm2; with a boron content of 0,96%, the structure of white cast iron is close to the eutectic, with impact toughness 0,98 J/cm2 ; at a boron content of 1,25% the structure of white cast iron is supereutectic and the impact toughness decreases to 0,68 J/cm2. With a change in the boron content from 0,8% to 1,25%, the amount of carbide phase in the structure of white cast iron increases, which leads to an increase in hardness from 53 to 59 HRC. The highest bending strength (Rmi=660,85 MPa) was obtained in white cast irons with a boron content of 0,23%. 


2020 ◽  
Vol 45 (2) ◽  
pp. 20-27
Author(s):  
Kayode I. Fesomade ◽  
Damilola D. Alewi ◽  
Saliu O. Seidu ◽  
Sheriff O. Saka ◽  
Bonaventure I. Osuide ◽  
...  

This study investigates the influence of palm kernel shell ash (PKSA) on mechanical and wear properties of white cast iron (WCI) particularly its influence on its microstructure, elemental composition, hardness and wear resistance. The PKSA was characterized to determine its elemental composition, and it was found to contain high amount of silicon (Si) and iron (Fe) followed by calcium (Ca) and other trace elements. The cast iron was cast into rods of specific dimension with sand casting method using rotary furnace to re-melt cast iron scrap. The WCI rods were then cut into bits for the various test. Heat treatment operation was carried out to determine its properties. Upon completion of the examinations, it was found that the PKSA increased the cementite phase within the matrix of the cast iron, and reduced the pearlitic phase and graphite formation, which gave it increased hardness, and perfect wear resistance due to the increment in carbon content and reduction in silicon content. Also, upon heat treatment, it was found that the PKSA reduced the pearlitic phase within the matrix of the cast iron, increases the formation of transformed ledeburites, austenitic dendrites and tempered graphite, which lead to increased machinability and ductility as well as to reduced hardness, and wear resistance when compared to non-heat treated samples.


2017 ◽  
Vol 68 (10) ◽  
pp. 2397-2401 ◽  
Author(s):  
Costel Dorel Florea ◽  
Ioan Carcea ◽  
Ramona Cimpoesu ◽  
Stefan Lucian Toma ◽  
Ioan Gabriel Sandu ◽  
...  

We obtained a new Fe-C material, a cast iron with high chromium content. The experimental material was analyzed by microstructural (SEM electronic) and chemical (EDAX characteristic X-ray dispersive energy analysis) point of view. The addition of chromium is aimed to increase the corrosion resistance and durability of FC250 castings used on industrial scale in the manufacture of automotive brake discs. The material was obtained using an industrial scale furnace. The experimental results showed a substantial increase in corrosion resistance by the addition of chromium.


2011 ◽  
Vol 117-119 ◽  
pp. 1084-1087
Author(s):  
Jing Pei Xie ◽  
Ai Qin Wang ◽  
Wen Yan Wang ◽  
Luo Li Li

Erosion wear experiments on Nickel-Chromium cast iron were tested by MCF-30 erosion test machine. The structure and surface morphology of these samples were analyzed by Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and XRD. The influences of the impact angle and acidity on erosion wear property were analyzed. The discipline of the erosion wear property was discussed as well. The experimental results indicate that after oil quench at 960°C and temper at 250°C, the alloy carbide (Fe, Cr)3C which works as the wear resistance skeleton distributes uniformly in the matrix ; the shape of erosion wear curve is “M”. and the biggest wear loss is when the impact angle is 60°; the erosion wear property is affected greatly by the strong acid, but is little even can be ignored when pH≥3. The erosion wear mechanism of Nickel-Chromium cast iron is selective wear.


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