scholarly journals Corrosion and Mechanical Properties of the Fe-W-Wo2 and Fe-Mo-MoO2 Nanocomposites

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Gulmira Yar-Mukhamedova ◽  
Maryna Ved’ ◽  
Nikolay Sakhnenko ◽  
Ann Karakurkchi ◽  
Iryna Yermolenko

Analyzing of composition electrolytic coatings’ application for the metal surface protection is considered. It is established that using different components for coatings’ modification gives possibility to obtain surfaces with expanding exploitation properties, in particular, with improved wearing and anticorrosion resistance. The new approach for protecting details which are made from cast irons by obtaining two kinds of composition coatings from binary alloys iron-molybdenum and iron-tungsten is proposed. It is found that the modification of iron by refractory metals up to 37 wt. % leads to a noticeable change in the microstructure of the coatings’ surface. It is established that the incorporation of refractory metals into the iron matrix is a good way to increase the microhardness of the surface by 2.5–3.5 times and rising of the wear resistance by 40%, as well as decreasing the friction coefficient by 3-4 times in comparison with the cast iron substrate. The research results can be used for surfaces hardening and protection in different industries.

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.


2021 ◽  
Vol 303 ◽  
pp. 01005
Author(s):  
Dmitry Lubyanoi ◽  
Evgeny Pudov ◽  
Evgeny Kuzin ◽  
Olga Semenova

The article shows the relevance of the use of alloyed cast iron in mining and metallurgical engineering. The article discusses the technologies for producing naturally alloyed cast iron. For working bodies and friction units of mining machines, such as pumps, coal pumps, hydrocyclones, crushers and mills. The main type of wear for them is abrasive. To increase the wear resistance of cast iron the production of cast iron has not been sufficiently studied yet. Although the use of cast iron in a complex alloyed with manganese, silicon, chromium, titanium and vanadium has been studied. The article studies the influence of manganese, titanium and vanadium on the mechanical properties and performance of machine parts and products of mining and metallurgical production in contact with high-temperature and highly abrasive media. The rational content of titanium and vanadium in gray cast irons is established in the range of 0.05-0.1%, which ensures their heat resistance and increases their wear resistance. The content of these elements can be increased to 0.07-0.12%. Bushings made of this cast iron have the required wear resistance and can increase the operational reliability of the equipment in the conditions of mining and metallurgical production. They also replace non-ferrous metals, as well as products obtained by powder metallurgy methods.


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.


2020 ◽  
Vol 299 ◽  
pp. 588-593
Author(s):  
Nataliia Vodolazskaya ◽  
Olga Sharaya

The way of solving the problem of surface wear of products from cast iron due to development of technological processes of its strengthening treatment is offered in this article. Receiving the hardened skins is reached by purposeful formation of the set structural condition of metal by methods of surface impregnation, i.e., modifying. Results of researches on thermochemical treatment of cast irons of grades EN-GJL-250, EN-JS1060 are presented The micro-structural analysis showed that with rising the saturation temperature and increasing the process duration the layer depth cartbonitration increases. Studying the samples for wear resistance carried out on stand ММ 295 showed that for grade EN-GJL-250 it increased 2,2 times, and for grade EN-JS1060 – 3 times as compared to the initial (non-modified) state. Experimental-industrial tests of products of cast iron (model accessory, parts of homogenizing pumps) after carbonitration permitted to state 2-4 times of its surface.


Author(s):  
Dhruv Patel ◽  
Devendra Parmar ◽  
Siddharthsinh Jadeja

Microstructural adaptation of cast iron alloys by inoculation is a well-known practice to swell their mechanical properties. In foundries, several inoculants have been used to refine grain structure, and to obtain uniform distribution of graphite flakes. Inoculation is one of the most critical steps in cast iron production. The effectiveness of inoculants depends on melt temperature, method of addition, type of inoculants, and holding time. In this paper, the effect of Ca-based, Ba-based, Ca-Ba based and Sr-based inoculants on microstructure and tensile properties of grey cast iron IS-210 and spheroidal graphite iron IS-1862 is reported. Results showed both Ca and Ba based inoculants were effective in obtaining uniform distribution of flaky and nodular graphite in IS-210, and IS-1862 cast irons, respectively. But in a case of Sr-based inoculant were highly effective for increase the nodularity of SG cast iron as well as succeed supreme yield strength for both grey and ductile cast iron. The amounts of ferrite in the as-cast matrix are excess with controlled granulometry for elimination of primary carbide in Sr-based inoculant.


2011 ◽  
Vol 284-286 ◽  
pp. 273-276
Author(s):  
Li Sheng Zhong ◽  
Yun Hua Xu ◽  
Xin Cheng Liu ◽  
Fang Xia Ye ◽  
Jing Lai Tian ◽  
...  

The method of infiltration casting plus heat treatment process employing chromium wires and cast iron applied to in-situ synthesized (Fe,Cr)7C3 particulates bundle reinforced iron matrix composites. The phase analysis, microstructure, microhardness and wear-resistance of composite were observed and measured. The results show that it is possible to fabricate (Fe,Cr)7C3 particulates bundle reinforced iron matrix composite produced by this technology, and a special structure which called particulates bundle was fabricated. (Fe,Cr)7C3 particulates bundle were distributed in the forms of granular, lath-shaped and hexagon-shaped in the particulates bundle. The macrohardness of particulates bundle was 52 HRC, and the relative wear resistance of the composites is 2.3—23 times higher than that of the cast iron.


1982 ◽  
Vol 104 (1) ◽  
pp. 60-65
Author(s):  
Yuichi Tanaka ◽  
Hakaru Saito ◽  
Ikuo Tokura ◽  
Katsuya Ikawa

The main purpose of this paper is to present some data on the mechanical and physical properties of compacted-vermicular graphite cast iron and to give a reasonable interpretation to the characteristics by using numerical indexes indicating the shape of graphite flakes in the structure. After describing the preparation of the material and a new method for measuring thermal diffusivity of the iron, the influence of kind and amount of alloy added for treatment and of cooling rate upon the graphite shape is discussed by using the indexes of the structure. The thermal diffusivities and mechanical characteristics such as tensile strength and hardness are shown as functions of the indexes to clarify the relationship between them. Furthermore, the present indexes are compared with those proposed earlier to find which is most suitable for the cast iron treated in this work. Authors propose a definition of compacted-vermicular graphite cast iron, which is reasonable from the physico-mechanical point of view, and also show some typical mechanical properties and measures required to produce such cast iron with desirable features.


2007 ◽  
Vol 26-28 ◽  
pp. 293-296 ◽  
Author(s):  
Guo Shang Zhang ◽  
Yi Min Gao ◽  
Jian Dong Xing ◽  
Shi Zhong Wei ◽  
Xi Liang Zhang

To improve the wear resistance of high chromium white cast iron under severe abrasive conditions, a composites layer was designed for wear surface, which were locally reinforced with WC particles. And the local composites were successfully fabricated by optimized centrifugal casting process. Then the interface between WC and iron matrix was analyzed with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). And three body wear tests were carried out on a self-made rig to investigate the wear resistance of the composites. For comparison, the wear tests of high chromium white cast iron were also carried out under the same conditions. The results show that: There are no defects such as inclusion, crack, gas pore and so on in the obtained composites layer, which with a uniform thickness of 10 mm. WC particles are homogeneously distributed in the composites layer and tightly bonded with the iron matrix. The WC particles are partially dissolved in the iron matrix during centrifugal casting. The elements W, C and Fe react to form new carbides such as Fe3W3C or M23C6, which precipitate around former WC particles during subsequent solidification. So the interface between WC particles and the iron matrix is a strong metallurgical bonding. WC particles in the composites layer can effectively resist cutting by the abrasive, and then protect the matrix. The wear resistance of the composites layer is 7.23 times of that of high chromium cast iron.


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