scholarly journals Microstructural evolution during austempering of a ASTM A-532 CLASS III type high chromium white cast iron undergoing abrasive wear

2017 ◽  
Vol 26 (46) ◽  
Author(s):  
Oscar Fabián Higuera-Cobos ◽  
Jeison Bucurú-Vasco ◽  
Andrés Felipe Loaiza-Patiño ◽  
Mónica Johanna Monsalve-Arias ◽  
Dairo Hernán Mesa-Grajales

This paper studies the influence of variables such as holding temperatures and times during austempering of High Chromium White Cast Iron (HCWCI), with the following chemical composition: Cr 25 %, C 3 %, Si 0.47 %, Mn 0.74 % and Mo 1.02 %. The aim of the austempering was to modify the percentage of retained austenite and its correlation to abrasive wear resistance under different conditions.Microhardness tests, SEM-EDS and XRD were performed to determine mechanical properties, chemical composition, and type of carbides and microstructures present, respectively. The tests complied with the ASTM G-65 standard. Results showed that the best performance against abrasion was achieved for austempering at 450 ºC with holding time of 6 hours.

2013 ◽  
Vol 58 (3) ◽  
pp. 973-976 ◽  
Author(s):  
D. Kopyciński ◽  
M. Kawalec ◽  
A. Szczęsny ◽  
R. Gilewski ◽  
S. Piasny

Abstract The resistance of castings to abrasive wear depends on the cast iron abrasive hardness ratio. It has been anticipated that the white cast iron structure will be changed by changing the type of metal matrix and the type of carbides present in this matrix, which will greatly expand the application area of castings under the harsh operating conditions of abrasive wear. Detailed metallographic analysis was carried out to see the structure obtained in selected types of white cast iron, i.e. with additions of chromium and vanadium. The study compares the results of abrasive wear resistance tests performed on the examined types of cast iron.


2012 ◽  
Vol 12 (4) ◽  
pp. 95-100 ◽  
Author(s):  
M. Kawalec ◽  
M. Górny

Abstract The paper presents the results of tests on the spheroidising treatment of vanadium carbides VC done with magnesium master alloy and mischmetal. It has been proved that the introduction of magnesium master alloy to an Fe-C-V system of eutectic composition made 34% of carbides crystallise in the form of spheroids. Adding mischmetal to the base alloy melt caused 28% of the vanadium carbides crystallise as dendrites. In base alloy without the microstructure-modifying additives, vanadium carbides crystallised in the form of a branched fibrous eutectic skeleton. Testing of mechanical properties has proved that the spheroidising treatment of VC carbides in high-vanadium cast iron increases the tensile strength by about 60% and elongation 14 - 21 times, depending on the type of the spheroidising agent used. Tribological studies have shown that high-vanadium cast iron with eutectic, dendritic and spheroidal carbides has the abrasive wear resistance more than twice as high as the abrasion-resistant cast steel.


2015 ◽  
Vol 56 (5) ◽  
pp. 720-725 ◽  
Author(s):  
Jatupon Opapaiboon ◽  
Prasonk Sricharoenchai ◽  
Sudsakorn Inthidech ◽  
Yasuhiro Matsubara

2014 ◽  
Vol 14 (1) ◽  
pp. 63-66 ◽  
Author(s):  
D. Kopyciński ◽  
S. Piasny ◽  
M. Kawalec ◽  
A. Madizhanova

Abstract The resistance of cast iron to abrasive wear depends on the metal abrasive hardness ratio. For example, hardness of the structural constituents of the cast iron metal matrix is lower than the hardness of ordinary silica sand. Also cementite, the basic component of unalloyed white cast iron, has hardness lower than the hardness of silica. Some resistance to the abrasive effect of the aforementioned silica sand can provide the chromium white cast iron containing in its structure a large amount of (Cr, Fe)7C3 carbides characterised by hardness higher than the hardness of the silica sand in question. In the present study, it has been anticipated that the white cast iron structure will be changed by changing the type of metal matrix and the type of carbides present in this matrix, which will greatly expand the application area of castings under the harsh operating conditions of abrasive wear. Moreover, the study compares the results of abrasive wear resistance tests performed on the examined types of cast iron. Tests of abrasive wear resistance were carried out on a Miller machine. Samples of standard dimensions were exposed to abrasion in a double to-and-fro movement, sliding against the bottom of a trough filled with an aqueous abrasive mixture containing SiC + distilled water. The obtained results of changes in the sample weight were approximated with a power curve and shown further in the study.


Author(s):  
Liyang Xiao ◽  
Pingan Xiao ◽  
Liviu Brândușan ◽  
Jinghong Gu ◽  
Zhongtao Li ◽  
...  

15 wt% Cr sintered High Chromium Cast Iron (HCCI) with full density was successfully prepared by Super-solidus Liquid Phase Sintering (SPLS) technique, with water atomized 15 wt% Cr high chromium cast iron powder as initial materials. Its densification behavior and microstructure evolution in SPLS process and mechanical properties were investigated systematically. Additionally, the impact abrasive wear resistance under different impact energies were also analyzed and compared with another sintered HCCI with 20 wt% Cr. The results indicated that sintering temperature has a strong influence on the sintered alloy’s density, hardness, impact toughness and bending strength. The M7C3 type (M is Cr and Fe) carbides were obviously coarsened as temperature increased and their rod-shaped branches were fully developed at the same time, thereby resulting in carbide network formation in the matrix. The reasonable sintering temperature range was 1195–1205 °C, and the optimum mechanical properties had the hardness of 63.9 HRC, bending strength of 2112.65 MPa and impact toughness of 7.92 J/cm2. What is more important impact abrasive wear test results indicated 15 wt% Cr sintered HCCI’s wear resistance could be comparable to 20 wt% Cr sintered HCCI under impact energy 1~3 J/cm2, and it is more cost effective.


2019 ◽  
Vol 61 (7) ◽  
pp. 690-694
Author(s):  
Tanju Teker ◽  
S. Osman Yilmaz ◽  
Erhan Kerkut

2019 ◽  
Vol 60 (2) ◽  
pp. 346-354 ◽  
Author(s):  
Jatupon Opapaiboon ◽  
Mawin Supradist Na Ayudhaya ◽  
Prasonk Sricharoenchai ◽  
Sudsakorn Inthidech ◽  
Yasuhiro Matsubara

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>


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