Increasing efficiency of plasma hardening by local cooling of surface by air with negative temperature

Bespalova, Alla; Лебедев, Владимир; Frolenkova, Olga; Knysh, Alexey; Dashkovskaya, Olga; Fayzulina, Oksana

doi:10.15587/1729-4061.2019.176825

Cited by 3 publications

(1 citation statement)

References 9 publications

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“…In the literature [14][15][16] it was shown that after PEH phase, structural transformations occur in the surface layer and the wear resistance and hardness of chromium-nickel steels increase. It is known that the reason for the increase in mechanical properties after plasma hardening is the formation of a finely dispersed martensitic structure [17,18]. In the literature [19,20] it is also shown that after plasma hardening of surface layer, martensite with a packet morphology and cementite interlayers are formed along the boundaries of martensite crystals.…”

Section: Introductionmentioning

confidence: 99%

Structural-phase transformations in 0.34C–1CRr–1Ni–1Mo–Fe steel during plasma electrolytic hardening

Rakhadilov

Kozhanova²,

Попова

et al. 2020

Materials Science-Poland

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Structural-phase transformations in 0.34C–1Cr–1Ni–1Mo–Fe steel during plasma electrolytic hardening were investigated. Electrolytic-plasma hardening of steel samples was carried out by surface quenching with rapid concentrated heating of the surface by plasma action and subsequent rapid cooling by heat removal from the depth of the sample by electrolyte jet. Plasma electrolytic hardening was carried out in the cathode mode in an electrolyte made from an aqueous solution containing 20 % sodium carbonate and 10 % carbamide. To study the structural-phase states of the modified layer, we used the method of transmission diffraction electron microscopy on thin foils. The study of steel samples was carried out before and after the plasma electrolytic hardening. Initially, the steel was a mixture of pearlite and ferrite grains. Surface hardening of 0.34C–1Cr–1Ni–1Mo–Fe ferrite-pearlite steel led to a change in the structural-phase state and the formation of a packet-lamellar martensite structure. It was found that PEH leads to distortion of the crystal lattice and the formation of long-range internal stresses, as well as to the release of small particles of cementite and carbide of M23C6 type, uniformly distributed throughout the volume of the material. Surface hardening led to the increase in all quantitative parameters of the fine structure (ρ, ρ ±, χ, σL, σd).

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Section: Introductionmentioning

confidence: 99%

Structural-phase transformations in 0.34C–1CRr–1Ni–1Mo–Fe steel during plasma electrolytic hardening

Rakhadilov

Kozhanova²,

Попова

et al. 2020

Materials Science-Poland

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Effect of Electrolytic-Plasma Surface Treatment on Structure, Mechanical, and Tribological Properties of Grade 1 Wheel Steel

et al. 2022

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Changes in structure, hardness and crack resistance of plasma-strengthened steel 65G

Kossanova,

Kanayev,

Tolkynbayev

et al. 2023

Izv. vysš. učebn. zaved., Čern. metall.

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The present paper describes the research of structure, hardness and crack resistance indicators before and after plasma treatment of 65G steel of a ploughshare part. As a result of plasma treatment, we obtained the modified layer with increased hardness in the range of 980 – 3558 HV with increase in 3.6 times. Metallographic studies showed that pearlitic-ferritic structure of the original metal transforms into needle martensite with high hardness and strength due to plasma hardening. It is recommended to determine the impact toughness by the Drozdowski method, in which a fatigue crack is pre-created on a special vibrator. Also, before the fatigue crack was grown, lateral V-shaped notches of different depths were made on the sample lateral surface. The relative crack length, λ, varied from 0.27 to 0.65. According to the results of compression tests, it was found that there was a small movement of cracks in the hardened samples in the range from 1.3 to 5.6 mm. The initial unstrengthened samples are in a more brittle state than the quenched ones, and accordingly, significant fracture is observed in the conditions of artificial cracking. The evaluation of 65G steel samples for crack resistance by impact bending tests with subsequent oscillographing showed that plasma hardening inhibits crack growth by increasing impact toughness. Thus, the use of plasma hardening is effective in surface hardening of 65G steel, in particular ploughshares which are constantly exposed to mechanical stresses, friction and wear.

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Increasing efficiency of plasma hardening by local cooling of surface by air with negative temperature

Cited by 3 publications

References 9 publications

Structural-phase transformations in 0.34C–1CRr–1Ni–1Mo–Fe steel during plasma electrolytic hardening

Structural-phase transformations in 0.34C–1CRr–1Ni–1Mo–Fe steel during plasma electrolytic hardening

Effect of Electrolytic-Plasma Surface Treatment on Structure, Mechanical, and Tribological Properties of Grade 1 Wheel Steel

Changes in structure, hardness and crack resistance of plasma-strengthened steel 65G

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