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The heat flux densities through thin layers of casting slag have been measured with a soft cooling heat flux probe which made smooth probe/slag interfaces. Thus the contact resistance was avoided. The evaluated effective thermal conductivities were applied, together with the data on the contact resistance, to compute the “system conductivities” existing in the continuous casting “system” water cooled copper/slag/strand. The refractive index and absorption spectrum were measured and used to deduce functions for the radiative and conductive (phonon) conductivities. Although precise values could not be obtained, due to the many assumptions involved, the data indicate that the conductive conductivity does not change drastically at high temperatures and on melting. 相似文献
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The heat transfer through layers of casting flux has been studied with a laboratory set-up which consists of a water-cooled heat flux probe made of copper and an electrically heated steel plate with a trough to hold the flux sample. The measured heat flux density values were converted to system conductivities ksys which contain the radiation/conduction conductivity in the flux layer and the contact resistance at the probe side. It was found that ksys is almost independent from the layer thickness. Ten commercial casting fluxes were investigated and the data for ksys are given as functions of composition and strand surface temperature. 相似文献
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Jordan Pavlossoglou 《国际钢铁研究》1983,54(2):73-78
Presentation of the stages of mathematical modelling technique of heat transfer process in a horizontal continuous thin strip casting of steel on a multi-layered bed. Analytical solution of the mechanistic model of the process. Also presentation of a balance between sensible and latent heat of the metal, and radiation losses from the upper surface and conduction through the “substrate”. Calculation of the time to achieve complete solidification. Results from the model and comparison with experimental data. 相似文献
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介绍了模拟结晶器内渣膜形成的实验方法, 综述了国内外学者在保护渣传热方面所做的研究工作, 包括固态渣膜的界面热阻、保护渣的导热系数、辐射传热以及渣膜的光学性质, 并提出了今后在渣膜形成及传热研究中有待进一步完善的内容和方向.现有的研究结果表明利用热丝法可以对渣膜的形成过程进行原位观察, 采用水冷铜探头法可以获取用于研究渣膜微观组织的固态渣膜样品.渣膜的界面热阻在0.0002~0.002 m2·K·W-1之间.在800℃以下, 保护渣的导热系数在1.0~2.0 W·m-1·K-1范围内, 且随温度的升高而逐渐增加.渣膜中的晶体一方面可以增加渣膜的界面热阻, 另一方面可以提高固态渣膜的反射率, 起到降低辐射热流的作用.此外, 过渡族金属氧化物的加入以及固态渣膜中弥散分布的微小颗粒也能改变渣膜的光学性质, 从而影响通过渣膜的辐射传热. 相似文献
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The influence of running water on spray water cooling is experimentally looked at with the aid of a stationary working experimental plant. The running water was fed separately to the sample from above as a defined water film by using a slot nozzle. In addition to the spray nozzle pre-pressure, the velocity of the running water at the slot nozzle exit and the temperature of the running water, the angle of inclination of the sample plane was also varied. By employing three different full cone spray nozzles and setting different nozzle distances, a range of 450 to 2000 l/(m2·min) of the water impingement density was covered. To estimate the marginal influences, samples of 20 × 20 mm as well as 30 × 30 mm were used. Studies of initially pure spray water cooling without the additional running water film revealed a dependency of the heat transfer on the spray water impingement density, the spray water velocity and also the angle of inclination of the sample plane. For nozzles with a low water impingement density, a superimposing of a running water film on the spray water revealed a sharp increase in the heat transfer coefficients compared to pure spray water cooling. For nozzles with a high water impingement density and, therefore, with a high heat transfer already even for pure spray water cooling, the increase of the heat transfer coefficient is minor. 相似文献
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Les Strezov Joe Herbertson Geoffrey R. Belton 《Metallurgical and Materials Transactions B》2000,31(5):1023-1030
An experimental study of initial solidification of 304 stainless steel melts in direct contact with copper substrates under conditions approximating the meniscus region of a strip caster has highlighted the importance of interfacial heat transfer during the first 30 ms of contact. The mechanisms governing initial heat transfer are strongly influenced by dynamic wetting phenomena. This has been illustrated experimentally by the effects of the buildup and melting of oxide films such as manganese silicates at the interface during successive immersions, by the role of surface active agents such as tellurium in the melt, and by the use of specially designed substrate textures to control contact areas. This article is based on a presentation made in the “Geoffrey Belton Memorial Symposium,” held in January 2000, in Sydney, Australia, under the joint sponsorship of ISS and TMS. 相似文献
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Christian Khler Rudolf Jeschar Reinhard Scholz Jacek Slowik Günter Borchardt 《国际钢铁研究》1990,61(7):295-301
For the cooling of steels in the continuous casting process it is necessary to know the heat transfer from the solidifying strand to the cooling water to enable calculation of the secondary cooling zone. Previous investigations have only determined this variable for non-oxidizing metallic surfaces. For many steels cast in practice, however, the formation of oxide layers prevents a direct transfer of the previous results. In the present research the influence of the oxide layers on the heat transfer has been investigated for spay-water cooling. Results have shown that heat transfer in the range of stable film boiling is determined for a constant spray-water temperature in the same way as for non-oxidizing metals, i.e. using the water mass flux density ·s only. The changed surface qualities resulting from the oxide formation cause the Leidenfrost temperature, however, to shift considerably to higher values. 相似文献
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Calculations are presented for the interaction of heat and fluid flow in the continuous casting of steel. In Part 1 it is shown that for typical superheat conditions the solidification process and the profile of the solidus line are relatively insensitive to the flow pattern in the molten phase. In Part 2 expressions are developed for predicting the dispersion of a tracer added to the molten pool, in the solidified slab. This dispersion is markedly affected by the flow pattern, thus tracer techniques may be used for characterizing the conditions in the molten pool. The effect of mixing on the floatability of inclusions is examined in Part 3. It is found that mixing may appreciably modify the relationship between particle size and floatability. 相似文献
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连铸碱性中间包覆盖剂的实验室研究 总被引:1,自引:0,他引:1
本文介绍了包钢连铸中间包覆盖剂配方的设计思路及设计原则,并对所设计的碱性中间包覆盖剂的各种物化性能,测试方法作了介绍,表明这种碱笥覆盖剂保温性能好,同时具有较强的防止钢液二次氧化及吸收A12O3等非金属夹杂的能力,对中间包内衬及长水口侵蚀也较小。 相似文献
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