2 The data has been used to calculate thermal stress and strain. 3.2 Calculation of the surface heat transfer coefficient 3.2.1 3.3. The surface heat transfer coefficient can be determined using the equation combined with the cooling curve 5, the result 9. Two experiments with a detectable vapor film in the early quenching showed that the temperature dropped to Generate a low 1 before 650! value. In other experiments, the Shan value increased steadily from the minimum value of 850 until the maximum value was recorded at 350. In each type of quenching, the maximum value of 1 is obviously consistent, because the temperature that produces the maximum is the same. The loudness of the conductivity coefficient, the number is the cooling curve in the chrysanthemum test sequence of a single sample can be used to determine the surface heat transfer coefficient obtained when the thick steel plate is quenched. This requires Equation 2, where the depth of the measured temperature below the surface needs to be accurately known. The small error in equation 2 will lead to calculation 1! Larger error. So there is an error of 0.2, the actual value is 18, when, then! The value produces unacceptable errors. Therefore, when the cooling curve is measured, the steel plates are cut along the plane containing the thermocouple junctions, and their depth is measured to the nearest ± 0., Below. The steel plate of the freshly ground surface is quenched by water to obtain 5 cooling curves, from which the value is calculated, and the influence of temperature on 3. Although all the curves have obvious maximum values ​​in the boiling stage, their dispersion is large, and the maximum value is The change between 2000850012 people is far greater than the value obtained by 3.3 steel bars. The temperature range corresponding to the maximum value is between 2805101. Because the steam film is not completely absent once the temperature drops below 700, the steam film either does not exist or the maintenance time is very short. The average value obtained from the temperature of each surface is 1013. These 3 results of the quenching of the unoxidized sample alone 18 the average value of the result 0 The result of the turbid quenching in the oil sample with the surface oxidation The surface heat transfer coefficient of the steel plate during the quenching process Make sure that Zhenjiang 212013, School of Materials Science and Engineering, Jiangsu University of Technology, Zhu Shouxing compiles Guang in 2550 water quenched 1250 polymer, the temperature is 1! The effect of value. The boiling temperature range will vary from 750 to 150, which is more similar to that obtained with pure water. However, its maximum value is lower than the value under water quenching conditions, and there are two different peaks. The h value of the trough between the two maximum values ​​at T is much higher than the 4 value in the vapor film stage. Surface temperature and heat transfer coefficient of steel plate when quenched in oil! The relationship between 12, the Zhongming species has a limited boiling stage and a very low peak, corresponding to about 2 000 Jia, 121. The results of quenching with different degrees of oxidation on the surface of the steel plate are very consistent, and the results are quite discrete with the results of water quenching. 1012. 3.3 After the temperature changes across the steel plate, the calculated value of the temperature gradient is compared with the test value. Obviously, although the temperature gradient measured in the later stage of water quenching is slightly larger than the calculated value, the comparison between the 3 water quenching 1 oil quenching and the predicted distribution is halfway up to the heat transfer coefficient of the garment. It is related to several quenching problems, and can be used in future articles on thermal stress and strain grate girder. According to the calculation of the accuracy of thermal stress and strain value. Although there will still be significant differences in the boiling stage, the generation of the surface oxide insulation layer increases the stability of the steam film stage As a result of the changes, they are all affected by the formation of oxide films. Moreaux et al. Proposed the coordination of the presence of a thermal insulation layer on the steel surface and the high cooling rate, which is exactly the opposite of what is described in this article. However, it is worth noting that although the surface heat transfer coefficient calculated from 3.3 steel bars and Equation 1 is relatively small, the results obtained are only slightly smaller than those obtained by a more accurate method for calculating thick sections. Therefore, although some assumptions based on low-precision technology are obviously not completely correct, but this very simple method can get an acceptable 1! value. The results obtained do not make it clear that the 25 water quenched 1250 polymerization is an exaggeration of the temperature gradient calculated at the beginning. In oil quenching, although the deviation between the calculated value of the temperature gradient and the experimental value is reduced in the later stage of quenching, the calculated value is still exaggerated. The values ​​involved in the calculation of temperature distribution are provided by 85 316 laboratory. 4Data obtained from similar materials. The constant used in the calculation of 13 is averaged from the value in 4. Will be used as a variable to slightly improve the relationship between calculations and experiments, but it will greatly increase the cost of calculation time. It takes 4 units to calculate the temperature distribution, which is the minimum number of units required to obtain the correct result 14. The quenching fluid is superior to water. To have an important effect on the quenching cooling curve, the polymer concentration is higher. Even if the maximum concentration is used, the heat transfer coefficient obtained in the boiling stage is only slightly lower than the lower limit obtained in the same stage of water quenching. 3. In addition, the reduction in the heat transfer coefficient formed by the polymer quenching fluid may be caused by the precipitation of the polymer at the steam film stage. Related to the steel surface. In addition, the value obtained in the steam film stage is much lower than 1 obtained in the same stage of water quenching! Value 3. Finally, it is easier to obtain a stable vapor film in the 1250 polymer quenching solution of 25-water quenched steel surface than in water alone. The surface heat transfer coefficient obtained by oil quenching is actually less than that produced by the above two media. The h value obtained in the boiling stage does not exceed 2000 W, 12, the time for this enhanced heat transfer is very limited. The heat dissipation rate of the extended oil-quenched steam film stage is very slow until the sample temperature drops below 520. Considering the large dispersion of the cooling curve measured by the experiment, it can be considered that the test measured 40! The temperature distribution and calculation of the steel plate predict the temperature gradient generated at any time during the quenching process of the steel plate. 5 Conclusion In the initial stage of water quenching, the presence of an insulating oxide film on the workpiece surface is conducive to the formation of a stable vapor film. In the steam film stage, the surface heat transfer coefficient is ⑴ soil tear 21. The average maximum value of the surface heat transfer coefficient obtained in the water quenching boiling stage is 3500 Jia Jiu 2 Min Luoren 12 200 185002 range, the heat transfer coefficient obtained at 0 relative to pure water quenching liquid when there is an oxide film surface, in order to effectively reduce The coefficient requires the water quenching 1250 polymer quenching medium to obtain the heat transfer coefficient of oil quenching fluid in water is very low, the maximum is 2, double Bian and the boiling stage is very short. The surface heat transfer coefficient determined by the approximate method of Equation 1 is much lower than the value obtained by the explicit difference method at any specified temperature. However, the accuracy of this simple method is sufficient for some applications. To calculate the residual stress, it is important to use the most accurate data possible. Therefore, in this case, it is recommended to use the finite difference method to obtain the surface heat transfer coefficient. The meaning of the letter generation used in the text is as follows: heat transfer coefficient, 121; the number of nodes in the half section of the steel plate; 1 the number of time intervals; 1 the mass of the sample, compare the GD and the number of time intervals before recording; 1 time interval, 3; Distance between points; 0 thermal diffusivity, 31; quenching liquid temperature, 0 initial temperature of the sample, temperature of the sample at the junction after a time interval, especially; 0, temperature of the sample at 1 moment, 05 The temperature at the hot end of the thermocouple after the time interval; into the thermal conductivity coefficient, density 13, standard deviation; subscript experimental value. Conventional and welding, the microstructure of the 1.1203 weld seam is conventionally heated, and a thin boundary film appears between the alumina and the active welding material. In contrast to this, the boundary structure between the welded alumina and the welding material is very continuous and has a very thick reaction layer. In other words, when the sample is heated, the dielectric loss of alumina increases, so the roughness is directly coupled with microwave radiation 6. 4 Conclusion This review illustrates the great potential of using microwave radiation to treat materials such as sintering and welding. It has been shown that the correct choice of microwave frequencies such as 280 and 2.450 can significantly improve the sintering ability of ceramics. The progress shows that the microwave radiation can be focused into a thin beam, which is convenient for the material. There is no other heat source to replace it. Finally, it was pointed out that microwave radiation can form high-density plasma, which can sinter ceramics onto metals at ultra-high speed. Sipimo Hair Essence SPRAY LUXURY Mens Hair Products,Hair Regrowth Treatment,Female Hair Loss Treatment,Hair Loss Treatment For Men Shenzhen Sipimo Technology Co., Ltd , https://www.sipimotech.com
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