scholarly journals Selection of rational electrochemical methods for controlling the efficiency of machining of corrosion-resistant steel

2021 ◽  
Vol 2131 (4) ◽  
pp. 042016
Author(s):  
Yu Astsaturov ◽  
S Solovyov ◽  
V Zhigulsky

Abstract The article discusses methods of controlling the processes of mechanical processing based on electrochemical effects. The corresponding anodic polarization curves of 1X18H9T steel obtained in electrolyte solutions without and with stirring are presented. The article discusses methods of machining processes control based on electrochemical effects. Lubricating and cooling technological media (LCTM) used in machining are in most cases electrolytes, therefore, electrochemical processes and phenomena actively occur during contact dynamic machining. It is possible to control the processes of machining by acting on the system elements of the tool - LCTM- part, in particular by activating the LCTM and reducing the strength characteristics of the processed steel in the cutting zone. A reserve for increasing the efficiency of mechanical processing can be the composition selection of the applied LCTM, combined with the simultaneous electrochemical polarization of the treated surface of friction pair parts. It was found that when cutting, the efficiency of machining and the chip shapes are changed, which is explained by the influence of the current density on the strength of the processed steel. In the conditions of machining, complex dynamic processes occur due to the rotation of the work piece and/or tool, so it is necessary to take into account the hydrodynamic phenomena and processes that arise in this case. Electrode potentials are considered to be the most important characteristic of the metal cutting process. The potential of the system can regulate such processes and indicators as wear and surface micro hardness. Anodic polarization curves of the steel 1X18H9T obtained in various electrolyte solutions without stirring and with stirring on a rotating disk electrode are given. The study allowed determining the factors affecting the processes occurring in the cutting zone and to identify rational current densities due to simulating the conditions of real technological processes of the combined steel processing. The increase in the processing intensity of the steel 1X18H9T with the cutting zone polarization is associated with the action of factors activating the selective anodic dissolution of the processed alloy.

2020 ◽  
Vol 2020 (3) ◽  
pp. 4-10
Author(s):  
Oleg Kirillov ◽  
Vladislav Smolencev ◽  
Evgeniy Kotukov

The purpose of the work is the application of a non-profiled electrode-brush for mating surfaces machining including that in crossed channels. To achieve the goal set there were problems under solution: the development of essential equipment, electrode-tools, the selection of working environment, the optimization of combined machining modes. To solve the problems set there are used basis regulations of the theory: electric and combined methods of machining, the mathematical apparatus of probability theories and mathematical statistics. In the paper the developed and manufactured plants and electrode-tools are shown. The recommended machining conditions, working environment are shown. The equipment is presented with a small-size plant for high-speed machining with an electrode-brush and a portable plant fixed on a drill rod that with the use of operating fluid recommended allows reducing considerably the terms and cost of metal cutting equipment updating for machining with electric field imposition. In the paper there are considered standard parts: nozzles, ejector bodies, parts of piping hydro-systems. The results of machining parts with crossed channels are shown. The application of processing by an electrode-brush with high circumferential velocities with regard to the work-piece from 35 m/sec and higher allows manufacturing products with the set values. The application of an electrode-brush is efficient for mating surfaces combined machining.


1980 ◽  
Vol 45 (8) ◽  
pp. 2272-2282 ◽  
Author(s):  
Jan Balej ◽  
Martin Kadeřávek

Preparation of peroxodisulphates by electrolysis of mixed solutions of sulphuric acid and various sulphates was studied at low degree of conversion; the partial polarization curves of peroxodisulphate formation and of oxygen evolution obtained from the overall anodic polarization curves and current yields of the principal anodic processes were examined. The mechanism of the effect of various cations on the rate of anodic formation of peroxodisulfates is discussed.


Author(s):  
V.L. Zakovorotny ◽  
V.E. Gvindzhiliya

High precision metal-cutting machines ensure that the programmed machine actuator trajectories correspond to the real ones. For lathes these are the trajectories of the longitudinal and transverse calipers of the system, as well as the spindle. The purpose of processing is to produce parts of a given quality while minimizing the manufacturing costs. The condition of the dynamic cutting system, determined by the trajectories of forces and deformations, affects the quality indicators of parts and the cutting efficiency, which depends on the intensity of tool wear. The properties of the system change depending on the phase trajectory of the power of irreversible transformations of the energy supplied to the cutting zone by the work performed. Their changes related with the evolution of the parameters of the dynamic link formed by cutting are manifested in the development of tool wear and changes in the quality of the part. Thus, the power of irreversible energy transformations is one of the internal factors causing changes in the output characteristics of processing and the state of the process. In this regard, when processing on machine tools, there is a problem of synergistic coordination of external control (for example, the CNC program) with internal one, the source of which is the irreversible transformation of the energy supplied to the cutting zone. The article considers the problem of synergetic coordination of external and internal controls during cutting process, the solution of which will allow increasing the efficiency of processing on CNC machines. A mathematical model of a controlled dynamic cutting system and control algorithms are proposed to improve the efficiency of processing parts of a given quality while minimizing the intensity of tool wear. Testing of the developed algorithms has shown that their use reduces the cost of manufacturing parts by 1.2.


CORROSION ◽  
10.5006/3871 ◽  
2021 ◽  
Author(s):  
Rodney Santandrea ◽  
Simone BRASIL ◽  
Leila Reznik ◽  
Ladimir Carvalho ◽  
Luiz Miranda

E-pH diagrams are usually built from thermodynamic databases available in the literature or from specific software. However, depending on the conditions and the chemical species defined for elaborating a diagram, it may present completely different immunity, passivation, and corrosion domains. In order to obtain a result closer to a real system, experimental E-pH diagrams can be built from polarization curves obtained in the evaluated conditions. This work discloses the construction of a diagram for the Nb-H<sub>2</sub>O system at 25°C from theoretical study and the specific selection of chemical species in the solutions through computer simulations. The polarization curves for the construction of the experimental diagram were gathered without the use of buffer solutions and under pH monitoring in the solution bulk throughout all assays. The methodology proposed was considered adequate since, from experimental data, a final result compatible with the classic diagram for the Nb-H<sub>2</sub>O system and the excellent corrosion resistance of niobium in aqueous media were achieved.


2011 ◽  
Vol 314-316 ◽  
pp. 1449-1455 ◽  
Author(s):  
Hua Shen ◽  
He Liang ◽  
Wei Dong Yang ◽  
Bing Xiang Liu ◽  
Tian Shu Li ◽  
...  

In this paper, AL-Mg-Mn-RE series alloys are becamed object of study.They are prouced with pure alumimum, pure Mg,electrolytic Mn and mix rich Ce rare earth. The effect of rare earth content on the resistance of the Al-Mg-Mn-RE series alloys are investigated by using Anodic polarization curves, electrochemical impendance spectroscopy. The results showed that their corrosivity is influenced by RE content in aluminum alloys.NO.3.3 impedance of Al-Mg-Mn-RE alloys is larger in the Nyquist diagram and its corrosion current of alloy decreases obviously. Then corrosivity of alloy is the best and the RE content is 0.3%,When the RE content is higher or lower than it that corrosivity isn’t improved but descended.


2021 ◽  
Vol 13 (3) ◽  
pp. 23-36
Author(s):  
Desalegn Wogaso ◽  
Mohammed Hamda

In metal forming, friction has a negative effect on the deformation load & energy requirements, homogeneity of metal flow, quality of formed surfaces, etc.; however, its effect can be reduced through the use of proper lubricants. Mostly, in industrial applications, selection of proper lubricant for specific material is challenging and quantification of magnitude of friction at diework piece interface is essential. Hence, for metallic alloys, a realistic friction factor is needed to be known and used at the diework piece interface for better control of deformation process. Thus, this research, generally, aims at experimental investigation of the friction behavior of aluminum AA4032 alloy and selection of suitable lubricant for its effective processing using ring compression test and finite element (FE) simulations. Meanwhile, the effect of metal surface conditions and different lubricants namely palm oil, grease, emulsion oil and dry conditions on the friction behaviour has been evaluated. A commercial FEM software, DEFORM 3D, is used to analyze the flow of metal, determine the geometry changes of the specimen and generate friction calibration curves. The results revealed that the nature of metal surface and lubricating conditions have significantly affected the metal flow pattern, deformation load requirement, induced effective stress and strain, and geometry of the metal. The friction factor at die-work piece is determined for different lubricating conditions. Among lubricants employed, palm oil is found to be suitable and effective for industrial processing of aluminium AA4032 alloy, specifically for forging. The FE simulation results are in a good agreement with the experimental one.


2015 ◽  
Vol 808 ◽  
pp. 40-47 ◽  
Author(s):  
Raluca Daicu ◽  
Gheorghe Oancea

Processing metallic materials by cutting using good electricity conductor cutting edges it appears an electrical current due mainly to the temperature in the cutting zone. Analyzing of the electrical current the information about the unfolding mode of the cutting process can be obtained. The cutting electrical current can be used in several applications: the estimation of the temperature in the cutting zone, the estimation of the cutting forces, the identification of the wear state of the cutting edge etc. The first researches were started in Russia and they were based on the utilization of the cutting electrical current to measure the temperature in the cutting zone. Afterwards, other applications were identified in the literature and the researches were extended in other countries like India, Japan, USA, Brazil, France, Bangladesh and Romania. This paper presents a review of the researches about the electrical current which appears at cutting process.


2014 ◽  
Vol 984-985 ◽  
pp. 15-24 ◽  
Author(s):  
S. Srikiran ◽  
K. Ramji ◽  
B. Satyanarayana

The generation of heat during machining at the cutting zone adversely affects the surface finish and tool life. The heat at the cutting zone, which plays a negative role due to poor thermal conductivity, resistance to wear, high strength at high temperatures and chemical degradation can be overcome by the use of proper lubrication. Advancements in the field of tribology have led to the use of solid lubricants replacing the conventional flood coolants. This work involves the use of nanoparticulate graphite powder as a lubricant in turning operations whose performance is judged in terms of cutting forces, tool temperature and surface finish of the work piece. The experimentation revealed the increase in cutting forces and the tool temperature when the solid lubricant used is decreased in particle size. The surface finish deteriorated with the decrease in particle size of the lubricant in the nanoregime.Keywords-Turning, Solid lubricant, Graphite, Minimum Quantity Lubrication, nano–particles,Weight percentage,Frictioncoefficient.


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