854611245有关热电偶测量的中英文翻译资料.doc

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1、利用热电偶测量50吨金属陶瓷锆硼化物端盖转炉中的金属均值温度钢的质量和产量在转炉冶炼过程中的生产效率取决于对金属的温度控制程度。因此，在整个流程中必需控制实时温度。用热电偶测量温度是测量液态金属温度最有效的方法。热电偶测试在工业条件下的一个50吨转炉中进行热电偶测试，结果发现计量特性最稳定的热电偶是PR30 / 6热电偶。所有后续实验，与此热电偶有关。为了防止液态金属破坏热电偶，我们使用三层气密端盖。三层气密端盖是用耐热锆硼化物制作的。锆硼化物端盖耐久性由化学作用而产生的物质对它们的腐蚀和流动金属流动的侵蚀造成的磨损所决定。它们的高耐火度和化学性质的稳定性是由化合物中的强化学键和价电子所决定。

2、其中硼化物由是内部元素的原子中不完整电子层的电子和晶体晶格中的硼原子组成。，许多的氧气转炉锆硼化物端盖损耗严重，因为有非均匀加热金属，使反应区温度可能会超过2500。在这种流动的状态下，它有时可能使带有硼化物端盖的转换器与金属渣进行接触。该转换器产生的炉渣含有氧化亚铁（FeO），它构成了中间化合物，在转移过程中金属里面大量的杂质被空气中氧气氧化。被氧化的杂质氧化性比较高而锆及硼有还原性，在温度为800左右锆及硼不会被氧化，如果温度超过1600锆及硼会被氧化（这是在转换器的情况下），其耐火度降低。在锆硼化物端盖表面，形成氧化锆，是一种破坏臭氧层的氧化物，所以要随时清洗，因此该端盖的保护成为主要问

3、题。设计转换器和50吨转炉时，应该将热电偶通过金属套管固定在转换器的低圆锥形部分内层。在墨西哥社会环境保护协会中展出了由乌克兰和苏维埃社会主义共和国的科学家共同开发了新的方法，他们是通过在转换器的底部和炉渣之间插入热电偶的方法来避免锆硼化物的氧化。该锆硼化物端盖被封装在一个狭窄的刚玉管内，并在刚玉管的一端，由一个盖帽来盖住。这种保护手段，使热电偶在一个金属管内进行测温。在第一次实验中，刚玉端盖因长时间工作，已经被液态金属所封闭。有关的疑虑是，通过刚玉端盖液态金属的可能进入刚玉管而与热电偶接触。在第一次安装热电偶实验时，铁水渗透到刚玉端盖内，当它凝固时，密封了刚玉管，从而自动封装了热电偶。受到刚

4、玉管保护的热电偶在安装拆卸，高温加热和与含水量高的耐火粘土接触时不会受到损坏。一块导流板，一块或两块以上的突起砖与端盖两边的耐火砖组成结构是为了保护刚玉管不受到损坏正如所料，在金属液体含量较低时，金属液体液面位于靠近转换器的底部那里，热电偶容易被氧化。在低于200毫米的深度这个水平时，在金属表面持续5-8分钟就被氧化。在320毫米的水平，持续15至19分钟。在安装转换器的底部，最终使整个冶炼过程中热电偶性能稳定。通过建立的调查，与炉渣的化学反应相比，液体的流动对金属端盖耐久性的影响是微不足道的。该端盖从转换器的底部安装到耐火砖里面减少与流动液体的接触，这并不能提高金属端盖耐久性。把热电偶插入到

5、测试地点时，我们应该确定转换器的温度控制在哪个层次。在转换器对流空气中含有氧气的基础上，我们假设液态金属流量和金属温度在转换器的外围是均匀的，由于热电偶的金属管安装在不同的位置，在冷却添加外加剂的时刻开始，也是在金属温度迅速变化，也是由温度变低使空气产生对流的过程中，热电偶安装在距离320和800毫米的转换器的底部是否被氧化，该热电偶金属管安装在不同深度的位置上，几乎没有产生对金属温度产生任何影响的，热电偶安装在靠近金属表面有微小的冷却补充作用。因此，人们发现对于有硼化物端盖的热电偶，安装在50吨转换器最合适的测量区，是距离转换器的底部200-500毫米处。事实证明，浇注已后的钢可能仍然存在影

6、响端盖的炉渣。对于确定动态误差的测量，我们平常使用的热电偶方法是放置在端盖底部，使暴露于复杂的热交环境中。冶炼过程中控制温度，以防止温度过高，并把金属浇注时温度下降一些。在此期间，温度变化率是在10-40/min的范围内变化，动态误差将在7-30的范围内。但是，通过这些信息，在动态误差校正的理论上可以很容易地得出误差减少到可以忽略不计。恒温的热电偶自由端控制具有特殊的重要性。对温度的依赖，转换器的外壳，在上述两哥方面是在转换器的操作就开始固定。外壳温度达到400时，第一个实验中在自由端恒温控制是借助的是空气流动，它的目的是为了在一个特殊的金属管内引入的空气。后来的恒温控制是借助了水箱冷却方法，

7、使用一种铜合金（99.4%铜和0.6镍）。在同一时间，在补偿的自由端控制的热电偶自由端温度电路的电阻值降低。MEASUREMENT OF THE METAL TEMPERATUREIN 50-TON CONVERTERS BY MEANS OF THERMOCOUPLESPROTECTED BY CERMET ZIRCONIUM-BORIDE END CAPSS. M. Serdyuk, M. I. Korobko, S. K. Sobolev,A. S. Sizenko, B. K. Kachur, and K. R. VlasovInstitute of Automation of the

8、 State Planning Commission, Ukr. SSR,and Institute of Problems in the Study of Materials, Academy of Sciences, Ukr. SSRTranslated from Poroshkovaya Metallurgiya, No. 1 (19),pp. 91-95, January-February, 1964Original article submitted September 6, 1968The quality of steel and the output and efficiency

9、 of converter production during the smelting process depend to a considerable extent on the metal temperature. Therefore, continuous temperature control is necessary during the blowing-through process.Measurement by means of thermocouples is considered to be the most efficient method for measuring t

10、he temperature of the liquid metal. A tungsten-molybdenum, a tungsten-molybdenum with aluminum (Central Scientific Research Institute of Ferrous Metallurgy), a platinorhodium-platinum, and a platinorhodium-platinum PR 30/6 thermocouple were tested during the operation of a 50-ton converter under ind

11、ustrial conditions. It was found that the most stable thermocouple with the necessary metrological characteristics was the PR 30/6 thermocouple. All the subsequent experiments were performed with this thermocouple.In order to protect the thermocouple from destruction by liquid metal, we used three-l

12、ayer gastight end caps, which were developed on the basis of heat-resistant zirconium-boride cases. The durability of zirconium-boride end caps was basically determined with respect to the chemical action which the stag exerted on them and with respect to the erosion wear caused by metal flow. It is

13、 known 1, 2 that zirconium-boride end caps can be exposed to liquid metal in Martin furnaces for several hours. Their high refractoriness and chemical stability in molten steels can be explained by the strong chemical bond of the compound, in which, besides valence electrons, also electrons of inter

14、nal incomplete electron shells of the elements atoms participate, and also by the structure of borides, where the frame of the crystal lattice consists of boron atoms 5.The operating conditions of zirconium-boride end caps are more severe in an oxygen converter, since there are large convection curr

15、ents of nonuniformly heated metal (local overheatings are possible), and the temperature in the reaction zone :may exceed 2500 C. As a result of this flow, it is possible that the end cap sometimes comes into contact with the converter slag carried by the metal.The converter reduction slag contains

16、a large amount of ferrous oxide FeO, which constitutes the intermediate compound that transfers the oxygen from the gaseous phase to the interior of the metal for the oxidation of impurities. The slag activity with respect to oxygen is very high. Zirconium and boron have an affinity to oxygen and ar

17、e actively oxidized at temperatures as low as 800 If the slag temperature exceeds 1600 C (which is the case in the converter), the end cap material, regardless of its high refractoriness, oxidizes from the surface, thus forming ZrO 2 and tO3 oxides, which are readily washed away by the slag, during

18、which complex silicates are formed due to thepresence of SiOz in the slag. As a result, the end cap dissolves in the slag until it fails mechanically in three to eight minutes. Therefore, the protection of the end cap constitutes the main problem.The design of the converter proper and the caisson of

19、 the 50-ton converter are such that the thermocouple can be introduced into the metal only through the casing and the lining of the converters lower conical part (Fig. 1). In* The zirconium-boride cases were developed at IMSS, Academy of Sciences, Ukr. SSR, under the supervision of G. V. Samsonov, C

20、orresponding Member, Academy of Sciences, Ukr. SSR.order to test the resistance of the end caps in the metal, they were inserted through the lining at the same level betweenthe bottom and the slag.The thermoelectrodes were encased in a narrow alundum tube (Fig. 2), and the junction was place in an a

21、lundum end cap, which was protected by means of a zirconiumboride cap, after which the thermocouple was place in a metallic tube. After the first experiments, the alundum end cap was made longer in order to protect the thermoeouple from shorting by the metal that has penetrated the lining. The misgi

22、vings concerning the possibility of the metal escaping through the entrance opening were not justified.During the first melting after the thermocouple was installed, the molten iron penetrated the thermoeouple entrance opening, sometimes even appearing on the outside of the casing, but it solidified

23、, thereby automatically sealing the thermocouple. The metallic tube protected the thermocouple from damage during the laying and heating of the lining and also from the moisture in refractory clay.A deflector (Fig. 2, 1) consisting of one or two bricks was provided above the protruding end cap in or

24、der to protect it from being damaged by a piece of brick in layingthe upper rows of lining, a piece of ore, or a piece of lime when cooling additions are introduced in the bath.As was expected, the resistance of the end pieces was greater when theywere located closer to the converters bottom where t

25、he amount of slag emulsion in the metal was lower. End caps mounted at the metal surface lasted 5-8 min. At a depth of 200 mm below this level, they lasted 15-19 min. At a level of 320 mm from the converters bottom, the end caps lasted throughout the entire smelting process.It has been established b

26、y investigations that, in comparison with the chemical action of slag, the effect of metal convection flow on the durability of end caps is negligible. The end caps fitted into the lining (Fig, 1, 3) were screened from the flow by refractory brick. This did not improve their resistance.Simultaneousl

27、y with testing the resistance of end caps at the insertion place, we determined the degree to which the temperature readings were representative of the temperature of the converter bath. On the basis of the converters symmetry with respect to the oxygen stream, we assumed that the convective metal f

28、low and the metal temperature were uniform along the converters perimeter. With the thermocouples installed at different levels in the metal zone, we recorded the beginning and the rate of changes in the metal temperature at the moment when the cooling admixtures were added and also the rate of temp

29、erature increase during the blowing-through process. The thermocouples were mounted at distances of 320 and 800 mm from the converters bottom.The placement of the thermocouple at different depths in the metal hardly exerted any influence on the riseof the metal temperature during the blowing-through

30、 process (Fig. 3). The thermocouples installed closer to the metal surface were found to be more sensitive to the action of cooling additions. Thus, it was found that, for zirconinm-boride end caps, the most suitable measurement zone in 50-ton converters is the region within 200-500 mm from the conv

31、erters bottom. The lower limit is determined by the fact that the slag that has remained after the pouring of steel may affect the resistance of the end caps. For determining the dynamic measurement error, we used the average time constant of the thermocouple, which was placed in the end cap and exp

32、osed to complex heat exchange conditions.The information on temperature is used during the second half of smelting in order to prevent overheating and to bring the metal to the assigned pouring temperature. During this period, the temperature variation rate lies within 10- 40 so that the dynamic err

33、or will be in the 7-a0 range. However, by feeding this information to a computer, a theoretical correction for the dynamic error can readily be introduced and the error reduced to a negligible quantity.Thermostatic control of the thermocouples free ends is of special importance. In dependence on its

34、 heating, the converters Casing, where the above ends are fastened at the beginning of the converters operation, can have a temperature of 70-150 C along the lining. At the end Of operation, the casing temperature attains 400C. In the first experiments, the thermostatic control of the free ends was

35、effected by means of a stream of air, for which the ends were introduced in a special tube. Later, thermostatic control was effected by means of a water-cooled box. Copper alloy TP (99.4ocopper and.6% nickel) was used for the conductor lead. At the same time, the resistance of the resistor in the ci

36、rcuit for compensating the temperature of the thermocouples free ends in the automatic potentiometer was reduced.URE CITED1.G. V. Samsonov, P. S. Kislyi, A. D. Panasyuk, A. G. Strelehenko, I. G. Khavrunyak, and G. N. Serikova,Ogneupory, No. 2 (1961).2.V. S. Kocho, A. G. Strelchenko, and I. G. Khavru

37、nyak, Coll.: Complex Automation of Steel Production inMartin Furnaces in Russian (1963).3.S, G. Manasev, Investigation of the Bessemer Process in Russian, Metallurgizdat, Moscow (1957).4.I. P. Bardin, S. G. Afanasev, M. M. Shumov, and Z. D. Ipsltein, Use of Oxygen in the Converter Productionof Steel in Russian, Metallurgizdat, Moscow (1959).5.G. V. Samsonov, High-Melting Compounds in Russian, Metallurgizdat, Moscow (1963).6.H. Trenkler, Ein Jahr L.-D Stahl Voest (1953).All