Theoretical basis of justification of electromechanical hardening modes of machine parts

Erokhin, M. N.; Pastukhov, Alexander; Golubev, I.G.; Kazantsev, S. P.

doi:10.22616/erdev.2020.19.tf032

Cited by 7 publications

(4 citation statements)

References 4 publications

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“…Plasma quenching of products of various grades of steel is one of the ways to significantly increase the reliability and durability of equipment and tools, when it is impossible to harden by volumetric heat treatment, surfacing or other methods (Aizawa 2019, Afriansyah et al 2019, Erokhin et al 2020). Despite the difference in the physical processes underlying a particular method of surface hardening of metals (plasma, laser, electron-beam, etc.…”

Section: Resultsmentioning

confidence: 99%

Experimental Studies of Operability of Hardened Cutting Edges of Parts

Sharaya

Pastukhov

Timashov

et al. 2022

Rural Development 2019

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The operability of machine and tool parts is often determined by the state of the working surface. It is on the surface that cracks arise, wear and corrosion processes begin. The presence of defects, the degree and depth of hardening, the level of residual internal stresses, the structure, the nature of the transition to the base material, most often determine the reliability and service life of parts and structures. Based on a critical review of hardening methods, it was found that one of the promising ones is the effect on the treated surface of a plasma jet of different power density. To ensure wear resistance of the working edges, the surface was treated with low-temperature plasma at an indirect arc plasmatron installation. The work investigated the phase and structural transformations after plasma coating on model samples of steel 65G, studied the structure and built microhardness profiles. Optimal parameters of plasma processing of articles are determined: distance from plasmatron -30 mm, rotation speed -10 s -1 , heating time -10 s. The established optimal modes of hardening treatment were used for plasma hardening using the example of an instrument (spiral drills made of steel grades R6M5, R6AM5 and 11R3AM3F2) under production conditions. For all types of drills, it was possible to obtain a hardened layer of 1-1.5 mm deep from the surface. According to the results of metallographic analysis, the microstructure of the hardened layer contained a white, non-etchable in acids zone with a high microhardness of up to 12000 MPa, the depth of which reached up to 0.4 mm; then there was a structure consisting of martensite and residual austenite with a microhardness of up to 9000 MPa. Tests of experimental drills for resistance, carried out in production conditions, showed an increase in their resource by 2 times compared to a tool that did not undergo plasma hardening, confirmed the possibility of multiple regrind within the hardened layer.

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Section: Resultsmentioning

confidence: 99%

Experimental Studies of Operability of Hardened Cutting Edges of Parts

Sharaya

Pastukhov

Timashov

et al. 2022

Rural Development 2019

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“…From the practice of electromechanical processing of machine parts, it is known that the quality of hardening of samples is influenced by the following factors: 1) current intensity in the secondary winding Ir = X1 [A]; 2) the effort is in contact "the toola detail" Fk = X2 [N]. As function of a response we accept: 1) hardness of the hardened surfaces HRC = Y (on Rockwell's units) [5][6][7]. The range and intervals of variation of factors are taken taking into account the theoretical justification: 1) X1 = Ir = 800...1200 A with an interval ΔI = 200 A; 2) X2 = Fk = 100...300 N with interval ΔF = 100 N [5][6][7].…”

Section: Methodsmentioning

confidence: 99%

“…As function of a response we accept: 1) hardness of the hardened surfaces HRC = Y (on Rockwell's units) [5][6][7]. The range and intervals of variation of factors are taken taking into account the theoretical justification: 1) X1 = Ir = 800...1200 A with an interval ΔI = 200 A; 2) X2 = Fk = 100...300 N with interval ΔF = 100 N [5][6][7]. The coding of experiments, factors and response functions are presented in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Method of justification of machine parts hardening modes

Pastukhov

Sharaya

Timashov

et al. 2021

20th International Scientific Conference Engineering for Rural Development Proceedings

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Based on an overview of methods for hardening and restoring parts of agricultural machines, it has been found that the methods currently used are highly labour intensive and are not well suited for hardening the cutting edge of tillage machine discs. A method of electromechanical hardening of ploughshare discs due to simultaneous thermal action and plastic deformation is disclosed. Electromechanical hardening modes are justified on the example of standard cylindrical samples. The developed technique contains the following stages: determining the steel grade of a part; planning of the experiment based on the plan of the full two-factor three-level experiment with selection of influences and response function; experimental hardening of laboratory samples at the installation; microstructural analysis of hardened samples; numerical processing of experiment results. Based on the optical emission analysis, it was found that the samples are made of steel 65G. The factors of influence are: current strength X1(Ir) = 800...1200 A on the reinforcing tool in the form of a roller and the pressing force X2(Fk) = 100...300 N of the tool to the part. The hardness of the surface layer Y(HRC) is adopted as the response function. Microstructural analysis showed that a layer consisting of several zones was formed on the hardened surface of the sample: white, light non-flowing and dark martensitic, passing into the ferrite-pearlite structure of the base. On the basis of multiple regression analysis, an empirical mathematical model is obtained and its graphical interpretation in the studied area of factors values is given. According to the criterion of providing wear resistance of working edges of disks, maximum hardness is achieved at current strength X1(Ir) = 1060 A and force X2(Fk) = 210 N in the contact zone. Developed technique and tested modes of electromechanical hardening are suitable for development of process of hardening of disk ploughshares of grain-grass seeders.

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“…Erokhin M.N., Novikov V.S. [2][3] found that the average wear of the share was 33.5 g/ha. Wear of implements in contact with the soil occurs as a result of friction and microscopic cracks on the wear surface.…”

Section: Introductionmentioning

confidence: 98%