连铸中间包钢水温度控制 Temperature control of steel liquid of tundish in continuous casting process

连铸中间包钢水温度控制

在连铸过程中，保持钢水温度稳定，降低出钢温度，在较低的过热度条件下浇注，是保证浇注过程顺利进行以及铸坯质量达到要求的重要手段。中间包是储存、分配钢液的最后一个耐火材料容器，作为冶炼与连铸的中间环节，中间包在钢的生产过程中起着承上启下的作用。中间包调整钢液温度的作用，越来越被人们所重视。中间包流出的钢液温度就是钢的浇铸温度，钢水的浇注温度是浇注的重要工艺参数。合适的浇注温度是顺利连铸的前提，合适的浇注温度又是获得良好铸坯质量的基础。如果在中间包内钢水浇注的中期，钢液温度过低，则造成连铸后期钢液流动性差，钢中夹杂物增多，甚至产生水口堵塞等事故，迫使浇注中断;而如果钢液温度过高一方面必然迫使出钢温度提高，使钢铁产品质量变差及耐火材料损耗严重，另一方面限制了连铸机拉速的提高，容易引起钢水包水口失控，而且会使坯壳减薄和厚度不匀，增加了拉漏危险等。因此中间包内钢液温度是连铸操作制度的核心，是保证连铸坯质量的重要保障。

合格的钢液浇注温度是指出钢时符合工艺要求的温度。制定出钢温度，要根据中间包钢液的目标温度(所生产钢种的液相线温度加上合适的过热度)，并要考虑出钢至浇铸过程各环节的热量损耗来确定。钢液过热度过高或过低对钢的生产都不利。表1-1为中间包内钢液过热度过高或过低对连铸的影响。

Temperature control of steel liquid of tundish in continuous casting process

In the process of continuous casting, the stability of the molten steel temperature is an important means to ensure the smooth progress of the casting process and the casting quality to meet the requirements. The tundish is the last refractory container for storing and distributing steel liquid. As the tundish of smelting and continuous casting, the tundihs plays a role of connecting the previous and the following in the production process of steel. More and more attention is paid to the role of adjusting steel liquid temperature. The temperature of molten steel flowing out from the tundish is the casting temperature of steel, and the pouring temperature of molten steel is an important process parameter of pouring. Appropriate pouring temperature is the premise of smooth continuous casting, and appropriate pouring temperature is the basis of obtaining good casting quality. If the temperature of the liquid steel is too low in the middle stage of the molten steel is too low, the fluidity in the liquid steel is poor, the increase of inclusion in the steel, and even the blockage, the temperature increases the quality of the steel products and the refractory material is serious, on the other hand limit the speed of the continuous casting machine, cause the loss control of the nozzle outlet, and make the blank shell thinner and the thickness is uneven, increasing the risk of leakage. Therefore, the temperature of liquid steel in the middle package is the core of the continuous casting operation system and an important guarantee for ensuring the quality of continuous casting billet.

The qualified steel pouring temperature is the temperature that the steel meets the process requirements. The steel temperature should be determined according to the target temperature of the intermediate clad steel liquid (the liquid phase line temperature of the produced steel) and the heat loss of each link from the steel to the casting process. Steel liquid overheating too high or too low for the production of steel. Table 1-1 shows the influence of too high or too low overheating of the liquid steel in the middle package on continuous casting.

在装备水平和管理水平较差的炼钢车间，没有采用加热装置。于是为了防止连铸钢水温度过底而普遍采用了高温出钢。由于对出钢后的温度下降程度难以准确把握，虽然也知道高过热度浇铸不利于钢质量，但为了保证生产顺利进行往往控制在偏高的钢液过热度。这必将导致耐火材料侵蚀严重，钢的二次氧化加剧，钢中夹杂物增多。考虑到现在多炉连浇和多水口浇铸的操作，钢液过热度更应保持稳定。应当采取措施为:一是不同水口的钢流温度差不应过大，二是各钢包之间和每钢包浇铸过程中钢液温度应尽量保持恒定。总之，应使中间包内钢液过热度无论在空间上或在时间上都接近于稳定状态。因此，对中间包内钢液温度的变化规律及其控制的研究就显得尤为重要。

In the steel making workshop with poor equipment level and management level, no heating device is used. Therefore, in order to prevent the water temperature of continuous casting steel through the bottom and the general use of steel out at high temperature. Because it is difficult to accurately grasp the degree of temperature drop after the steel, although it is also known that the high overheat casting is not conducive to the steel quality, but in order to ensure the smooth production of the high steel liquid overheat is often controlled in order to ensure the smooth production. This will certainly lead to the serious erosion of refractory materials, the secondary oxidation of steel, and the increase of inclusions in steel. Considering the operation of multi-furnace continuous casting and multi-water outlet casting, the overheat of liquid steel should be kept stable. Measures should be taken as follows: first, the temperature difference of steel flow in different nozzle outlets should not be too large; second, the steel liquid temperature between each ladle should be kept as constant as possible in each ladle during the casting process. In short, the overheat of the inner steel contained in the middle bag should be close to the stable state both in space and in time. Therefore, it is particularly important to study the change law and control of the liquid steel temperature in the tundish.

钢水在中间包内的热损失主要是表面的辐射散热和中间包包衬的蓄热。据研究测定在表面无覆盖或覆盖不佳的情况下,钢水表面的辐射热损失占中间包内总共热损失的80%~90%。

用绝热板做内衬及砖衬(烘烤)的中间包浇注，钢水温降状况相似；使用绝热板浇注，前期温降较多，如果控制不好中包开浇温度，极易造成中包无法顺利开浇，出现中包冻包，冷包现象。同时在中包前后期容易出现中包散流，夹钢等现象。

砖衬中间包内钢水温降与包衬的烘烤状况有关，对4流小方还中间包的烘烤状况与浇注过程中砖衬吸热作测定计算表明，烘烤良好的中间包包衬吸热比烘烤差的包村吸热量少 1/3，包衬吸热主要在浇注前期，因此砖衬烘烤对浇注前期钢水的热损失有很大的影响。

同时在中包浇注过程中，包容以及钢水液面同样严重影响钢水温度，如果中包拉速过快，极易造成中包在钢包转换过程中，出现中包液面快速下降，中包内钢水容量快速减少，整体中包快速失温，中包温度快速下降。

The heat loss of molten steel in the tundish is mainly the radiation and heat dissipation of the surface and the heat storage of the middle bag lining. According to the study, the radiant heat loss of the molten steel surface accounts for 80%~90% of the total heat loss in the intermediate package.

For the tundish pouring with insulation plate and brick lining (baking), the steel liquid temperature lost temp process is similar; if the temperature drops fast at the early stage, if the pouring temperature is not controlled properly, the tundish cannot be cast smoothly, and the phenomenon of frozen and cold tundihs occurs. At the same time, it is easy to appear tundish casting stream dispersion, steel billet with much impurity  .

Brick lining tundish，the steel liquid temperature is related to the lining of baking condition, to 4 flow tundish baking condition and brick lining heat absorption in the process of casting determination calculation shows that baking good lining heat absorption than baking Bao Village heat less 1 / 3, lining heat absorption is mainly in the early stage of pouring, so brick lining baking heat loss of molten steel has a great influence.

At the same time, in the pouring process of the tundish, the inclusion and the molten steel level also seriously affect the temperature of the molten steel. If the tundish pulling speed is too fast, it is easy to cause the rapid decline of the liquid surface in the tundish, the molten steel capacity in the tundish is rapidly reduced, the overall tundish temp quickly loses , and the tundish temperature is rapidly decreased.