Increasing the Corrosion Resistance of Heat-Resistant Alloys for Parts of Power Equipment

Vahrusheva, V.S.; Hlushkova, Diana; Volchuk, V. M.; Nosova, T.V.; Mamhur, S.I.; Tsokur, N.I.; Bagrov, V.A.; Demchenko, S.V.; Ryzhkov, Y.V.; Scrypnikov, V.O.

doi:10.46813/2022-140-137

Cited by 16 publications

(11 citation statements)

References 6 publications

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“…Різні види оброблень застосовуються лише конкретно до заданого виробу. У деяких ситуаціях варто виконувати поверхневе зміцнення виробу [1][2][3].…”

Section: вступunclassified

Determining the Influence of Electro-Spark Alloying on the Strength Indicators of Machine Parts

Hlushkova,

Volchuk,

Zubkov

et al. 2024

Bulletin of KhNAHU

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Problems The strengthening of the case and striker was carried out by electric spark alloying in order to protect against corrosion, wear, sticking to the surface of contacting materials. The results of testing parts strengthened by electric spark alloying show that the wear resistance of parts increased by 1.3 times compared to the initial state of parts. Regression equations are obtained, which can be interpreted as a knowledge base for controlling the strength indicators of the striker body, allowing to control its residual resource during operation. It was established that the strength indicators increase when the fractal dimension of the sorbite component increases, since it has better strength indicators compared to the original ferrite-pearlite structure. Goal. In order to increase the wear resistance and fatigue strength of the material of hydraulic hammer parts, it is not always advisable to change the traditional technology of manufacturing the part and, in particular, the methods of its heat treatment. Different types of finishing are applied only specifically to the given product. In some cases, it is worth applying surface strengthening of the product. Currently, there are a number of surface strengthening technologies, each of which has its own advantages and disadvantages. Methodology. All parts were strengthened by electric spark alloying with tungsten. The power of the processing current was 1 kW. The peak, in addition to strengthening with tungsten, was additionally processed by electric spark alloying with chromium at a current of 1.5 kW. Surfaces processed by electric spark alloying were polished to obtain the roughness of the hardened surfaces of parts R and 04-08. Results. During the micro-examination of areas strengthened by electric spark alloying, which are outside the load zone during the test, it was established that the areas strengthened by electric spark alloying on the body and sleeve have a thickness of 10–40 μm and a hardness of Н V 600–650. On the strikers, the initial thickness of the strengthened layer is 20 μm with a hardness of НV 600-650. The strengthened zones in the section have the appearance of arc-shaped, embedded surface layers of metal parts, phases. There are no structural changes under this zone in the main metal. Originality. The microstructure of the base metal consists of sorbitol. The mechanical properties of the material of the device parts were determined at a temperature of 20 °C on samples cut in the axial and tangential directions. Since the obtained structure of sorbite was difficult to quantify by traditional methods of quantitative metallography, it was studied using the theory of fractals. The obtained results make it possible to forecast the strength indicators of the body of the hydraulic hammer striker based on the fractal dimension of photographs of the microstructure at a magnification of 100. Practical value. The structural changes that occur during the tests in the surface layers of the parts are characteristic of the phenomena of secondary hardening with a lower level of hardness than on the parts of the previous options. The relationship between the fractal dimension of the sorbite structure and the strength characteristics was established, which allows us to use the obtained results as a non-destructive method of controlling the strength of parts after electric spark alloying.

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Section: вступunclassified

Determining the Influence of Electro-Spark Alloying on the Strength Indicators of Machine Parts

Hlushkova,

Volchuk,

Zubkov

et al. 2024

Bulletin of KhNAHU

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“…Before welding coatings, due attention should be paid to the preparation of the surfaces of machine parts [ 18 ]. According to the condition of filler material deposition, the three most popular surfacing techniques utilized today are as follows: solution state (sole gel, electrochemical deposition [ 19 , 20 ], chemical solution deposition), gaseous state (ion beam-assisted deposition (IBAD), chemical vapour deposition (CVD)), physical vapour deposition (PVD) [ 21 , 22 ] and molten or semi-molten state (arc welding, plasma technology [ 23 , 24 ], spraying [ [25] , [26] , [27] , [28] ] and laser/electron beam [ 29 , 30 ]. Another issue is the shaping properties of surface layers to improve the tribological characteristic and wear resistance by various surface engineering methods including heat treatment [ 31 , 32 ] and thermochemical treatment (oxidation [ 33 , 34 ], carburizing, boriding, nitriding [ 35 ]) etc.…”

Section: Introductionmentioning

confidence: 99%

Prediction of phase composition and mechanical properties Fe–Cr–C–B–Ti–Cu hardfacing alloys: Modeling and experimental Validations

Lozynskyi,

Trembach,

Hossain

et al. 2024

Heliyon

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“…Flux-cored wires are widely used for hardfacing and the restoration of worn surfaces [32][33][34][35][36]. The hardfacing process consists forming a hardening layer of the deposited metal on surfaces subject to intense abrasive wear [37,38], impact abrasion [39][40][41][42], and other types of wear [43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Effect of Exothermic Additions in Core Filler on Arc Stability and Microstructure during Self-Shielded, Flux-Cored Arc Welding

Lozynskyi,

Trembach,

Katinas

et al. 2024

Crystals

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In the conditions of an energy crisis, an important issue is the increase in energy efficiency and productivity of welding and hardfacing processes. The article substantiates the perspective of using exothermic additives introduced into core filler for flux-cored wire arc welding processes as a relatively cheap additional heat source, reducing energy consumption when melting filler materials, and increasing the deposition rate. The mixture design (MD) was selected as the design method to optimize the average values of current and voltage, as well as arc stability parameters depending on core filler composition. This article studies the influence of the introduction of exothermic addition (EA), as well as the ratios CuO/C and CuO/Al on arc stability for the FCAW S process. Parameters characterizing arc stability were determined using an oscillograph, and from the obtained oscillograms, an analysis was conducted on arc voltage and welding current signals during flux-cored arc welding. It was determined that various methods can be used to evaluate arc stability, which can be divided into two groups: graphical (current and voltage cyclograms, box plots with frequency histograms, ellipse parameters plotted on current, and voltage cyclograms) and statistical (standard variation and coefficients of variation for welding current and arc voltage). In this paper, a comprehensive evaluation of arc stability depending on the composition of the cored wire filler was carried out. It was determined that the most stable current parameters were observed for the flux-cored wire electrode with an average exothermic addition content at the level of EA = 26.5–28.58 wt.% and a high carbon content (low values of CuO/C = 3.75). Conversely, the lowest values of arc stability (CV(U) and Std(U)) were observed during hardfacing with a flux-cored wire electrode with a high CuO/Al ratio ≥ 4.5 and a content of exothermic addition in the core filler below the average EA < 29 wt.%. Mathematical models of mean values, standard deviation, coefficient of variation for welding current, and arc voltage were developed. The results indicated that the response surface prediction models had good accuracy and prediction ability. The developed mathematical models showed that the ratio of oxidizing agent to reducing agent in the composition of exothermic addition (CuO/Al) had the greatest influence on the welding current and arc voltage characteristics under investigation. The percentage of exothermic mixture in the core filler (EA) only affected the average welding current (Iaw) and the average arc voltage (Uaw). The graphite content expressed through the CuO/C ratio had a significant impact on welding current parameters as well as the coefficient of variation of arc voltage (CV(U)). Two welding parameters were selected for optimization: the mean welding current (Iaw) and the standard deviation of arc voltage (Std(U)). The best arc stability when using exothermic addition CuO-Al in the core filler was observed at CuO/Al = 3.6–3.9, CuO/C = 3.5–4.26, and at an average EA content of 29–38 wt.%. The significant influence of the CuO/Al and CuO/C ratios on arc voltage parameters can also be explained by their impact on the elemental composition of the welding arc (copper, cupric oxide (CuO), and Al2O3). The more complete this reaction, the higher the amount of easily vaporized copper (Cu) in the arc plasma, enhancing arc stability. The influence of core filler composition on the microstructure of deposited metal of the Fe-Cr-Cu-Ti alloy system was investigated.

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Increasing the Corrosion Resistance of Heat-Resistant Alloys for Parts of Power Equipment

Cited by 16 publications

References 6 publications

Determining the Influence of Electro-Spark Alloying on the Strength Indicators of Machine Parts

Determining the Influence of Electro-Spark Alloying on the Strength Indicators of Machine Parts

Prediction of phase composition and mechanical properties Fe–Cr–C–B–Ti–Cu hardfacing alloys: Modeling and experimental Validations

Effect of Exothermic Additions in Core Filler on Arc Stability and Microstructure during Self-Shielded, Flux-Cored Arc Welding

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