High Wear Resistance of White Cast Iron Treated by Novel Process: Principle and Mechanism

2015 ◽  
Vol 46 (12) ◽  
pp. 5514-5525 ◽  
Author(s):  
Xiaoshuai Jia ◽  
Xunwei Zuo ◽  
Yu Liu ◽  
Nailu Chen ◽  
Yonghua Rong
2020 ◽  
Vol 62 (8) ◽  
pp. 788-792
Author(s):  
Tanju Teker ◽  
S. Osman Yilmaz ◽  
Tekirdağ Teker

Abstract White cast iron with about 12.7 wt.-% chromium was alloyed with Ni, W and Mo for heat treatment applications. Heat treatments were performed at a range of 850-1050 °C for 1 h in order to distribute M7C3 carbides homogeneously in an environment of high wear resistance. The contents of the C, Cr, Ni, Mo, Mn and Si elements selected for the alloys were similar, though a 6 wt.-% nickel concentration was chosen. Microstructural changes in the specimens were examined by scanning electron microscopy (SEM) and optical microscopy (OM). Macro-hardness, average carbide size and volume fraction were analyzed. Wear tests were carried out under different loads of 10, 20 and 30 N. It was seen that heat treatment changed the carbide size and homogeneous distribution of the carbides. Moreover, the addition of nickel to HCrWCI increased fracture toughness and reduced the wear rate.


2014 ◽  
Vol 14 (3) ◽  
pp. 33-36 ◽  
Author(s):  
M. Kawalec ◽  
J. Kozana

Abstract The cast alloys crystallizing in Fe-C-V system are classified as white cast iron, because all the carbon is bound in vanadium carbides. High vanadium cast iron has a very high abrasion resistance due to hard VC vanadium carbides. However, as opposed to ordinary white cast iron, this material can be treated using conventional machining tools. This article contains the results of the group of Fe-C-V alloys of various microstructure which are been tested metallographic, mechanical using an INSTRON machine and machinability with the method of drilling. The study shows that controlling the proper chemical composition can influence on the type and shape of the crystallized matrix and vanadium carbides. This makes it possible to obtain a high-vanadium cast iron with very high wear resistance while maintaining a good workability.


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>


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Alejandro González-Pociño ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano

In this article, the effects of an ionic nitriding treatment are analysed, together with deliberate variation of different thermal parameters associated with the destabilisation of austenite, on erosive wear resistance of white cast irons with 25% Cr. The methodology followed in this research was an experimental design, where six factors were analyzed by performing eight experiments. The thickness of the nitrided layer is much smaller than in white cast iron with lower percentages in Cr, never reaching 20 microns. The nitriding treatment entails considerable softening of the material underneath the nitriding layer. This softening behaviour becomes partially inhibited when the destabilisation temperature of austenite is 1100 °C and dwell times at such temperature are prolonged. This temperature seems to play a significant role in the solubilization of non-equilibrium eutectic carbides, formed during industrial solidification. The nitriding treatment leads to additional hardening, which, in these cases, favours a second destabilisation of austenite, with additional precipitation of secondary carbides and the transformation of retained austenite into martensite. Despite softening of the material, the nitriding treatment, together with air-cooling after destabilisation of the austenite, allows a noticeable increase in resistance to erosive wear.


Author(s):  
A. P. Chernysh

In this article, the plant for heat treatment of grain material, namely perfo-rated spiral operating part, developed by the authors was chosen as the object of improving the wear resistance. The research was conducted in the laboratory of the Technology of Metals and Machinery Repair Department of Kemerovo State Agricultural Institute. The aim of the research is to select the most appropriate method of hardening the functional surface of perforated spiral operating part with the use of low-cost anti-wear coatings. The basis for choosing the method of surfacing the coating was the use of a method of forming the technological repair units (TRU), which allowed electric spark treatment with unalloyed white cast iron.


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.


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.


2021 ◽  
Vol 1016 ◽  
pp. 56-62
Author(s):  
Carlos Camurri ◽  
Jasmín Maril ◽  
Eric Romero

The aim of this work was to study the wear behavior of high-chromium white cast iron of families ASTM A-532 II (B, D) and III A, used in mining equipment, in order to establish relationships between the wear resistance, hardness and microstructure of the alloys, with the ultimate purpose of predicting their resistance to abrasion. Samples from these cast irons were subjected to mechanical wear tests by rotating drum, then their micro/macro hardness was measured and microstructure analyzed by optical and scanning electron microscopy .It was found that when the macroscopic hardness differences were significant there was a strong correlation between the hardness and the loss of mass due to abrasion-impact wear. By contrast, when the alloys had similar hardness, the wear resistance was determined by morphology, size, and the distribution and connectivity of carbides and matrix and therefore was not predictable by an only simple hardness test.


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