Hardening-Related Deformations of Gear Wheels After Vacuum Carburising and Quenching in Gas

Stachurski, Wojciech; Zgórniak, P.; Sawicki, J.; Przybysz, Mateusz

doi:10.12913/22998624/67673

Cited by 14 publications

(5 citation statements)

References 6 publications

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“…The difference between the obtained results in terms of surface flatness of the outer and inner circles was the result of sample preparation for testing and, primarily, the quenching process. In the opinion of the authors, quenching from high temperatures results in the immediate occurrence of a martensitic transition and a "freezing" of the geometrical dimensions on the outer side of the element [10,14,15]. Consequently, the "deformation front" is pushed deep inside the element, and the inevitable changes in volume-related to transition of the material from austenite to martensite-take place in the inner parts of the element.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the single-piece flow model takes every single element through the exact same position and process conditions as the others, avoiding variations in the physical and metallurgical characteristics over the placement that the element occupies [2,3,12,13]. Additionally, in a 4D quenching chamber, the inflow of cooling gas from all sides and the rotation of parts are performed to support a uniform cooling effect [14,15]. The more uniform the parameters provided, especially during quenching, the better the expected regarding the distortions.…”

Section: Introductionmentioning

confidence: 99%

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Algorithm Scheme to Simulate the Distortions during Gas Quenching in a Single-Piece Flow Technology

et al. 2020

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Low-pressure carburizing followed by high-pressure quenching in single-piece flow technology has shown good results in avoiding distortions. For better control of specimen quality in these processes, developing numerical simulations can be beneficial. However, there is no commercial software able to simulate distortion formation during gas quenching that considers the complex fluid flow field and heat transfer coefficient as a function of space and time. For this reason, this paper proposes an algorithm scheme that aims for more refined results. Based on the physical phenomena involved, a numerical scheme was divided into five modules: diffusion module, fluid module, thermal module, phase transformation module, and mechanical module. In order to validate the simulation, the results were compared with the experimental data. The outcomes showed that the average difference between the numerical and experimental data for distortions was 1.7% for the outer diameter and 12% for the inner diameter of the steel element. Numerical simulation also showed the differences between deformations in the inner and outer diameters as they appear in the experimental data. Therefore, a numerical model capable of simulating distortions in the steel elements during high-pressure gas quenching after low-pressure carburizing using a single-piece flow technology was obtained, whereupon the complex fluid flow and variation of the heat transfer coefficient was considered.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Algorithm Scheme to Simulate the Distortions during Gas Quenching in a Single-Piece Flow Technology

et al. 2020

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“…External access to transportation chambers is ensured by loading and unloading locks. The "single piece flow method" is that individual workpiece passes through similar process conditions and positions in the furnace [37,38]. The method provides high precision and repeatability in comparison to conventional carburizing methods.…”

Section: Vacuum Carburising With Single-piece Flow Methods and Heat T...mentioning

confidence: 99%

The Influence of the Depth of Grinding on the Condition of the Surface Layer of 20MnCr5 Steel Ground with the Minimum Quantity Lubrication (MQL) Method

et al. 2022

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This paper describes the research on abrasive machining conditions and their influence on microhardness and residual stresses distribution in the technological surface layer of 20MnCr5 steel. The roughness of ground samples was also measured. Samples underwent a vacuum carburizing process (LPC) followed by high-pressure gas quenching (HPGQ) in a 4D quenching chamber. Processes were realized with a single-piece flow method. Then, the flat surfaces of samples were ground with a Vortex type IPA60EH20VTX alumina grinding wheel using a flat-surface grinder. The samples were ground to three depths of grinding (ae = 0.01; 0.02; 0.03 mm) with grinding fluid supply using either flood method (WET) or minimum quantity lubrication (MQL) method. The condition of the technological surface layer was described using microhardness and residual stresses, as well as some selected parameters of surface roughness. The results obtained revealed that changes in microhardness as compared to microhardness of the material before grinding were lower in samples ground with grinding fluid supplied with MQL method. At the same time, the values of residual stresses were also better for samples ground using MQL method. Furthermore, the use of grinding fluid fed with MQL method produced lower values of surface roughness compared to the parameters obtained with WET method. It was concluded that for the tested scope of machining conditions, the MQL method can be a favourable alternative to the flood method of supplying grinding fluid into the grinding zone.

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“…After quenching, carburised steel is often harder than raw steel. In this version, it can be used for any industrial applications where wear resistance under operating conditions is important [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Influence of Flow and Pressure of Carburising Mixture on Low-Pressure Carburising Process Efficiency

2022

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Low-pressure carburising (LPC) of steel is an industrially accepted method for improving the properties of a steel surface. LPC is environmentally friendly, does not cause intergranular oxidation and consumes less energy. Its effectiveness depends on the correct choice of process inputs. This paper aims to determine the effect of this type of carboniferous gas, pressure and flow rate on the efficiency of carbon transfer to the surface layer under low-pressure carburisation. A total of 40 disks of 16MnCr5 steel were carburised using pure acetylene or a mixture of acetylene, ethylene and hydrogen as a carboniferous gas, pressures of 2 or 6 hPa and two gas flow rates. The specimens were gravimetrically tested for the increase in the mass of carbon in the carburised layer. The results were analysed with U Mann–Whitney analysis and t-Student test. It was evidenced that carburising with pure acetylene resulted in a higher increase in carbon mass than carburising with the mixture (p < 0.05). Pressure and gas flow rates are important for carburising efficiency (p < 0.05).

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Hardening-Related Deformations of Gear Wheels After Vacuum Carburising and Quenching in Gas

Cited by 14 publications

References 6 publications

Algorithm Scheme to Simulate the Distortions during Gas Quenching in a Single-Piece Flow Technology

Algorithm Scheme to Simulate the Distortions during Gas Quenching in a Single-Piece Flow Technology

The Influence of the Depth of Grinding on the Condition of the Surface Layer of 20MnCr5 Steel Ground with the Minimum Quantity Lubrication (MQL) Method

Influence of Flow and Pressure of Carburising Mixture on Low-Pressure Carburising Process Efficiency

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