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Heat Treatment by Induction
Published in Valery Rudnev, Don Loveless, Raymond L. Cook, Handbook of Induction Heating, 2017
Valery Rudnev, Don Loveless, Raymond L. Cook
A typical practice for developing the cooling curve for a given alloy is to heat a sample of the material to the austenitizing temperature and then quenching it in the chosen quench medium under defined conditions. Thermocouples on the surface and center of the part are used to generate a curve for the temperature versus time. Most standard cooling curves are generated for immersion quenching, revealing three typical stages in the process of quenching the part to the temperature of the quench medium [162,166,167,172–175,339,429].
Experimental Study on Concentration Effects on the Supercooling of Phase Change Material-in-Water Nanoemulsions
Published in Heat Transfer Engineering, 2023
Ching-Jenq (C.J.) Ho, Shr-Chi Chen, Chi-Ming Lai
From Figures 3 and 4, the melting point decreased linearly as the DSC heating rate decreased, while the freezing point gradually increased as the DSC cooling rate decreased. However, in the figures, some freezing points deviated from the trend line; i.e., the cooling and freezing process was relatively unstable. The melting point can be defined by extending the melting point data toward a heating rate = 0, and the freezing point can be defined by extending the freezing point data toward a cooling rate = 0. As shown in the figures, the melting point can be defined by a single trend line, while for the freezing point, in addition to the 1st freezing point, there is another trend line generated by the delayed heat release of some PCMs, and this corresponding freezing point is called the 2nd freezing point. Finally, the melting and freezing points defined in the experiment were combined with the temperature calibration to calculate the deviations. After the deviations were added to the experimental values, the melting and freezing points were obtained. The latent heat can be obtained from the area under the DSC melting/cooling curve. Because some emulsions had two freezing points, two latent heats were generated during freezing. Therefore, the total latent heat released during freezing was the sum of the two latent heats. The relevant results are shown in Table 1.
Investigation of microstructural and mechanical properties of hot forged 31Mn4 dual phase steel with computer-aided simulations
Published in Canadian Metallurgical Quarterly, 2023
İlter Kilerci, Osman Çulha, Tuğçe Yağcı
The cooling data obtained by the hot forging process simulation of 31Mn4 steel yielding support clamp, was integrated into the material-specific CCT diagram obtained by JMatPro software. The material phase distributions after the cooling process were estimated by the cooling curve as shown in Figure 4. At this point, it should be emphasised that a systematic series of activities is carried out, which includes the evolution of academic knowledge into industrial applications. Before the FEM supported analysis, material data were produced in the virtual environment and measured in industrial practice by obtaining the chemical composition specific CCT diagram using a pyrometer. Then, the phase ratios were estimated with the CCT diagram by obtaining the air-cooling curve, and the deformation amounts on the cross-sectional basis were also optimised with the FEM supported forging simulations. The annealing temperature of the forging raw material and the cooling behaviour of the workpiece at the end of the forging process on the basis of variable cross-sections were analyzed and the outputs of the air-cooling process were compared with the theoretical findings. At the end of the simulation-supported optimisation processes of the process parameters, the same parameters were used in pilot productions to verify the study subject with real-time tests. According to this, it is seen that the workpiece will contain ferritic-pearlitic and bainitic phases at the end of the cooling process when material-specific CCT curve was evaluated by the cooling curve of the workpiece.
Solid Fraction Effect on Solidification of Semisolid Forging A380 Alloy
Published in Materials and Manufacturing Processes, 2022
Muhammad Hafiz Jahare, Mohd Hasbullah Idris, Wan Fahmin Faiz Wan Ali
The critical parameters during solidification are derived from the cooling curve of sample S1. A number of peaks and valleys from the first derivative curve signify the gradients of the cooling curve corresponding to the change in latent heat, which indicates phase formation. A further magnification on the liquidus region reveals several parameters of the solidifying melt, as depicted in Fig. 5(a). The initial solidification point (TL) is depicted at a starting point of an obvious increment from the lowest valley. Subsequently, the solidification endpoint (TS) is indicated by the end of a descended significant peak .[33] The maximum peak (TArrest) at 576.2°C (849.35 K) is the point which α-aluminum nucleation became stable while TU at 575.9°C (849.05 K) indicates minimum undercooling temperature and TG at 576.7°C (849.85 K) triggers the growth of primary α-Al dendrite. At 0.1 K/s cooling rate, S1 recorded an extended solidification time of 564.7 s and solidification range of 48°C as tabulated in Table 4.