On a possibility of replacing grey cast iron for manufacturing cast elements of electrolyzer gas collecting bell

2021 ◽  
Vol 77 (9) ◽  
pp. 1063-1070
Author(s):  
A. A. Usol’tsev ◽  
N. A. Kozyrev ◽  
S. V. Knyazev ◽  
A. I. Kutsenko ◽  
A. R. Mikhno
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Heat Resistance ◽  
High Strength ◽  
Grey Cast Iron ◽  
Simultaneous Formation ◽  
Metal Base ◽  
Spherical Graphite ◽  
Grey Cast ◽  
Graphite Inclusions

The main process leading to the destruction of the cast elements of gas-collection bell of electrolyzer, made of grey cast iron, is the oxidation of iron by oxygen, SO2 gas and sulfur vapors to form magnetite, hematite and pyrrhotin. The simultaneous formation of iron oxides and sulfides does not prevent further corrosion, since scale is formed with a loose structure that does not have protective properties. Reducing the length of the interfacial boundaries inside the material of the cast enables to reduce the rate of corrosion destruction, which can be achieved by modifying the cast iron to change the shape of graphite inclusions, i.e. obtaining high-strength cast iron with a spherical shape of graphite inclusions. However, the obtaining spherical graphite in cast iron using magnesium modification does not exclude the access of aggressive gases to the surface of the products and the possibility of their diffusion along the grain boundaries. It was shown that alloying can be an alternative, which leads not only to the exclusion of lamellar secretions of graphite in the structure of cast iron, but also to the formation of surface oxide layers based on the alloying element preventing the corrosion. Alloying with chromium gives cast iron high abrasive resistance due to the presence of a carbide component in the structure, as well as corrosion resistance due to the alloying of the metal base, heat resistance due to increasing the electrochemical potential of the metal base and creating a strong neutral oxide film on the surface of the castings, heat resistance, etc. An experimental comparative analysis of the corrosion resistance of cast iron used for manufacturing of gas collecting bell of electrolyzers showed that chromic cast iron ЧХ3 has a higher corrosion resistance than high-strength cast iron with spherical graphite ВЧ50 and much higher than grey cast iron with lamellar graphite. However, chromic cast iron ЧХ3 has low casting properties, is very sensitive to the cooling rate and has a large heterogeneity in structure, which makes it difficult to use it for the manufacture of gas collecting bell of electrolyzers.

Investigation of Grey Cast Iron Microstructure Influence on its Heat Resistance

2018 ◽  
Vol 284 ◽  
pp. 332-337 ◽  
Author(s):  
Konstantin N. Vdovin ◽  
M.V. Shubina ◽  
I.G. Shubin
Keyword(s):  
Cast Iron ◽  
Heat Resistance ◽  
Thermal Cycling ◽  
Grey Cast Iron ◽  
Matrix Composition ◽  
Compact Graphite ◽  
Grey Cast ◽  
Lamellar Graphite ◽  
Materials Used ◽  
Graphite Inclusions

Grey cast iron is one of the most common engineering materials used to make castings which work in thermal cycling. Under thermal cycling conditions, heat resistance is an important operational property of grey cast iron, which depends to the greatest extent on its structure – size and shape of the graphite inclusions, as well as the metal matrix composition. In this paper, the heat resistance of unalloyed grey cast iron with lamellar and compact graphite distributed in perlitic and perlitic-ferritic metal matrices was determined. The tests were carried out at temperatures of 500 – 800 °C. The results of the studies showed an insignificant difference of perlitic and perlitic-ferritic grey cast iron with lamellar graphite heat resistance. The heat resistance of perlitic ferritic grey cast iron with compact graphite is 16 – 48 % higher than the heat resistance of perlitic ferritic grey cast iron with lamellar graphite. Thus, when the shape of the graphite inclusions changed from lamellar to compact, a significant increase in the heat resistance of unalloyed grey cast iron occurred.

scholarly journals Corrosion resistance study of grey cast iron implanted with C, N, Cr and Cu ions

2017 ◽  
Vol 87 ◽  
pp. 092030 ◽  
Author(s):  
O Yu Usanova ◽  
L A Maryushin ◽  
A Yu Kazantsev ◽  
A I Dyukova
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Grey Cast Iron ◽  
Grey Cast ◽  
Cu Ions

Rust Is Not a Must. Improvement of Discs Corrosion Resistance by Tuning of Grey Cast Iron Alloying Elements and Microstructure

2020 ◽  
Author(s):  
Federico Bertasi ◽  
Bozena Dudzik ◽  
Alessandro Mancini ◽  
Marco Bandiera ◽  
Simone Biondo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Grey Cast Iron ◽  
Alloying Elements ◽  
Grey Cast

Research on Heat Resistance of As-Cast Ferritic Nodular Iron

2015 ◽  
Vol 1095 ◽  
pp. 184-187 ◽  
Author(s):  
Bao Yuan Li ◽  
Guo Shang Zhang ◽  
Shi Zhong Wei ◽  
Ji Wen Li
Keyword(s):  
Cast Iron ◽  
Thermal Stress ◽  
Heat Resistance ◽  
Thermal Shock ◽  
Oxidation Resistance ◽  
Fatigue Resistance ◽  
Grey Cast Iron ◽  
Nodular Iron ◽  
Grey Cast ◽  
Number Of Cycles

This article focuses on research into thermal shock fatigue resistance and oxidation resistance of as-cast ferritic nodular iron. The results show that the number of cycles required to crack nodular iron under the action of thermal stress is significantly higher than that of grey cast iron, and the rate at which cracks spread is lower compared with that of grey cast iron. When graphite is transformed from flakes into nodules, its decreased connectivity impedes the flow of oxygen during oxidization, thereby improving its oxidation resistance.

Increasing Wear Resistance of Chizel Tools Working Bodies Based on Improving the Metallographic Structure of Grey Cast Iron

2020 ◽  
Vol 299 ◽  
pp. 652-657
Author(s):  
Vadim A. Motorin ◽  
Ludmila V. Kostyleva ◽  
Dmitry S. Gapich
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Soil Layer ◽  
Grey Cast Iron ◽  
High Wear Resistance ◽  
Metal Base ◽  
Mold Making ◽  
Grey Cast ◽  
Working Bodies ◽  
The Given

The article concerns developing and implementing the technological principles for manufacturing the working bodies of chisel tools by casting grey cast iron with partial chilling of its working edges and surfaces interacting with the soil layer. High wear resistance of the working body is achieved by chilling its working part by means of a chill inserted into the mold, or by absence of coating in the corresponding zone of the mold. Severe overcooling of liquid cast iron contacting the chill or the metal surface of the mold causes crystallization of the meta-stable eutectics, and in the chilled part it acquires a ledeburite structure, the hardness being not lower than 64 HRC. At the same time, the bulk of the cast iron crystallizes in the stable system, forming austenitic-graphite eutectics and after complete cooling, it should have a pearlitic metal base, ensuring good machine ability of casting by cutting. Working surfaces and cutting edges of chisels are exposed to abrasive and chemical impacts of the soil, causing intense wear, the latter being the main reason for their failure. The utilization of the given technology will allow increasing service-life of the working bodies and improve the manufacturability, according to the criteria for labor intensity and casting mold making.

scholarly journals Development of High-Performance Enamel Coating on Grey Iron by Low-Temperature Sintering

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2183 ◽  
Author(s):  
Dan Song ◽  
Ren Tang ◽  
Falin Yang ◽  
Yanxin Qiao ◽  
Jiapeng Sun ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Low Temperature ◽  
High Performance ◽  
Alkali Metals ◽  
Enamel Coating ◽  
High Strength ◽  
Grey Cast Iron ◽  
Wear Volume ◽  
Grey Cast

In this study, we report on a low-temperature sintered enamel coating with a high-strength bonding and wear-resistance that protected a grey cast iron substrate. The SiO2–Al2O3–B2O3 composited prescription for the enamel coating was modified by the partial substitutions of SiO2 for B2O3 and alkali metals for Li2O. The optimized enamel coating was prepared by sintering at a relatively low temperature (730 °C) for seven minutes. Due to the composition of both the amorphous and crystalline phases, the enamel coating presented sufficient hardness and excellent wear resistance. The wear volume loss and the specific wear rate of the enamel coating were obviously lower than that of the metal substrate. The enamel coating can effectively improve the service life of the grey cast iron substrate in a complex frictional environment.

scholarly journals Corrosion Resistance of CoCrFeNiMn High Entropy Alloy Coating Prepared through Plasma Transfer Arc Claddings

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1876
Author(s):  
Pei-Hu Gao ◽  
Rui-Tao Fu ◽  
Bai-Yang Chen ◽  
Sheng-Cong Zeng ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Corrosion Resistance ◽  
Cast Iron ◽  
Corrosion Potential ◽  
Alloy Coating ◽  
Grey Cast Iron ◽  
High Entropy Alloy ◽  
Solid Solution Phase ◽  
High Entropy ◽  
Grey Cast

High entropy alloy attracts great attention for its high thermal stability and corrosion resistance. A CoCrFeNiMn high-entropy alloy coating was deposited on grey cast iron through plasma transfer arc cladding. It formed fine acicular martensite near the grey cast iron, with columnar grains perpendicular to the interface between the grey cast iron substrate and the cladding layer as well as dendrite in the middle part of the coatings. Simple FCC solid solutions present in the coatings which were similar to the powder’s structure. The coating had a microhardness of 300 ± 21.5 HV0.2 when the cladding current was 80 A for the solid solution strengthening. The HEA coating had the highest corrosion potential of −0.253 V when the plasma current was 60 A, which was much higher than the grey cast iron’s corrosion potential of −0.708 V. Meanwhile, the coating had a much lower corrosion current density of 9.075 × 10−7 mA/cm2 than the grey cast iron’s 2.4825 × 10−6 mA/cm2, which reflected that the CoCrFeNiMn HEA coating had much better corrosion resistance and lower corrosion rate than the grey cast iron for single FCC solid solution phase and a relatively higher concentration of Cr in the grain boundaries than in the grains and this could lead to corrosion protection effects.

scholarly journals RESTORATION OF THE CONSTRUCTION AND ROAD MACHINES’ DETAILS FROM GREY CAST IRON: IMPROVEMENT OF THE REPAIR DIMENSIONS’ METHOD EFFICIENCY

2019 ◽  
Vol 16 (6) ◽  
pp. 658-668
Author(s):  
V. E. Ovsyannikov ◽  
V. I. Vasilyev
Keyword(s):  
Cast Iron ◽  
High Strength ◽  
Grey Cast Iron ◽  
Special Device ◽  
Technical And Economic Analysis ◽  
Grey Cast ◽  
Final Manuscript ◽  
Friction Assemblies ◽  
Operational Failures ◽  
Technical Solutions

Introduction. The total mass of some grey cast iron details in construction and road machines reaches 60%. Cylinder blocks, parts of braking systems, flywheels, etc. are made of cast-iron. One of the main causes of operational failures (up to 70%) of construction and road machines is failure of friction units. Considering that the contacting parts in these units take the load mainly by surface layers. The operability looses at relatively small values of dimensional wear. Although mass wear of the part usually does not exceed 1%.Materials and methods. The authors carried out a comprehensive technical and economic analysis of repair methods of friction assemblies. As a result, the best combination of criteria was the repair size method. However, the strengthened layer was removed to the repair dimension by conventional reconditioning technology. At the same time grey cast iron was strengthened only by very expensive and labor-intensive methods, which in conditions of real repair production were not applicable. The authors considered the possibility of using a new method of strengthening iron parts in repair works.Results. The developed method strengthened grey cast iron with layer thickness up to 3 mm. The distinctive feature was that hardness of the strengthened layer in thickness increased. At the same time the microhardness increased in comparison with the initial grey iron more than 2 times and wear resistance became comparable to high-strength hardened stun.Discussion and conclusions. The authors obtain the best results with the usage of reducing atmosphere furnaces. In order to expand the scope of the method, the researches proposed to use a special device creating the necessary conditions in any furnace. The application of the proposed technical solutions increases the efficiency of the construction and road machines’ repair.The authors have read and approved the final manuscript. Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

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