When discussing refractory materials, we often hear a word - high temperature structural strength. So, what does this term refer to? How to evaluate it? Next, let's take a deeper look together!
PART.01
What is the high temperature structural strength of refractory materials?
High temperature structural strength is a key indicator to measure the performance of refractory products. It refers to the ability of materials to withstand pressure without deformation under high temperature. This indicator is usually evaluated by the load softening temperature. The load softening temperature is the temperature at which the refractory material begins to deform by gradually increasing the temperature under a specific pressure, and the temperature point when its compression deformation reaches 4% or 40%. These two temperature points are called the load softening start temperature and the softening point of 4% or 40% load softening, respectively, which provide us with important information about the material's ability to resist deformation at high temperatures.
It is worth noting that refractory materials usually show high compressive strength at room temperature. For example, ordinary clay bricks can withstand pressures up to 12.5Mpa, while other more advanced refractory bricks can withstand greater pressures. However, when the temperature rises, the strength of these materials will drop significantly. This is because high temperature causes the fusible components in the refractory bricks to melt prematurely and form a liquid phase, which significantly reduces its compressive strength.
In the kiln masonry, the refractory materials must not only withstand the test of high temperature, but also bear a certain weight load. Therefore, high-temperature structural strength has become an important criterion for evaluating the quality of refractory materials. Taking corundum bricks as an example, their refractoriness is as high as 2000℃, which is very suitable for molybdenum wire furnace tubes that need to withstand high temperatures of 1700~1800℃. This is because the molybdenum wire electric heating element is usually wound outside the corundum furnace tube, requiring the refractory material of the furnace lining to remain stable at high temperatures without softening and deformation, so as to avoid damage or even breakage to the electric heating element.
PART.02
High-temperature structural strength of refractory materials includes
The high-temperature structural strength of refractory materials is a comprehensive performance indicator, which covers many aspects, mainly including high-temperature load deformation temperature and high-temperature mechanical strength. High temperature load deformation temperature is a key indicator. It refers to the temperature point at which refractory products begin to deform or collapse significantly during continuous heating under specific pressure conditions. The determination of this temperature point is of great significance for evaluating the stability and service life of refractory materials in high temperature environments.
High temperature mechanical strength is another indispensable indicator. It measures the maximum compressive stress that refractory products can withstand under specific high temperature environments. This indicator is directly related to whether refractory materials can maintain their structural integrity and stability under high temperature conditions, thereby ensuring their safety and reliability during use. By comprehensively evaluating these two indicators, we can have a more comprehensive understanding of the performance of refractory materials in high temperature environments and provide a scientific basis for selecting suitable refractory materials.
PART.03
Factors affecting the load softening temperature (high temperature structural strength)
The factors affecting the load softening temperature in the high temperature structural strength of refractory materials are diverse and complex. The load softening temperatures of various refractory products show significant differences, which are mainly attributed to their unique chemical mineral composition, crystal structure, phase quantity ratio, and viscosity of the liquid phase during melting. For example, clay bricks have a larger temperature span in the process of deformation under load to destruction, while silica bricks have a relatively narrow temperature range, which just reflects the difference in high temperature resistance of different materials.
In order to improve the load softening temperature of refractory materials, we need to finely control the production process. The first task is to purify the raw materials to reduce the adverse effects of impurity elements on the high temperature performance of the material. Secondly, by appropriately increasing the firing temperature, the crystals can be better condensed and grown, thereby improving the structural stability of the material. At the same time, adding specific admixtures can improve the crystal structure of the material, which is also an effective way to increase the load softening temperature. In addition, increasing the pressure during the molding process can make the product more dense, while increasing the content of coarse particles can help increase the deformation temperature of the material in the initial stage. These specialized regulatory measures work together in the production process of refractory materials to enhance their stability and durability under high temperature and heavy load environments.
PART.04
Evaluation method of high temperature structural strength
Since high temperature structural strength is so important, how can we accurately evaluate it? At present, the method commonly used in the industry is to determine the load softening temperature of refractory materials.
① Methods and steps for determining the strength of high-temperature structures
The determination of the strength of high-temperature structures is a precise and highly specialized task, and its operation methods and steps must be strictly followed. In the preparation stage, representative refractory samples must be carefully selected to ensure that their size, shape and quality fully meet the test specifications. At the same time, a full set of high-precision testing equipment must be prepared, including a high-temperature furnace that can stably control the temperature, a pressure sensor with high sensitivity, and a deformation measuring instrument that can monitor and record the tiny deformation of the sample in real time.
After entering the test stage, the refractory sample must be placed securely in the high-temperature furnace and heated at a constant heating rate. During this process, a constant load must be applied to the sample using a pressure sensor to simulate the stress conditions under actual working conditions. At the same time, the deformation of the sample is continuously tracked and monitored by the deformation measuring instrument to ensure the accuracy and real-time nature of the data.
In the recording and analysis stage, it is necessary to record the deformation data of the sample at different temperatures in detail, especially the temperature at which the sample begins to deform, that is, the softening temperature under load. Through in-depth analysis of these data and combined with the drawing of the temperature-deformation curve, we can scientifically evaluate the structural strength of refractory materials in high temperature environments. This series of measurement steps not only requires operators to have rich professional knowledge and practical experience, but also requires high-precision instruments and equipment and a rigorous experimental attitude to ensure the reliability and accuracy of the test results.
② Formulation of high-temperature structural strength assessment standards
When formulating the assessment standards for high-temperature structural strength, we strictly follow the load-bearing softening temperature and other key performance data obtained through scientific experiments. Through in-depth analysis and comprehensive consideration of these data, we have built a scientific, rigorous and highly operational assessment system. This system not only makes a fine division of the requirements for high-temperature structural strength of different levels, but also clarifies the corresponding load-bearing softening temperature range according to actual application scenarios and needs, as an important basis for assessing the performance of refractory materials.
The formulation of this set of assessment standards aims to provide manufacturers with a clear direction for performance improvement, prompting them to continuously optimize production processes and improve product quality. At the same time, it also provides users with a scientific and reliable reference basis for selecting suitable refractory materials, ensuring that they can maintain excellent structural strength and stability in high-temperature working environments. The implementation of this set of standards will effectively promote the technological progress and standardized development of the refractory industry, and provide a solid guarantee for safe production and efficiency improvement in the high-temperature industrial field.
PART.05
The importance of high temperature structural strength
High temperature structural strength is a core indicator in the performance evaluation of refractory materials, and its importance cannot be ignored. In the extreme environment of high temperature and high pressure in industrial production, if the structural strength of refractory materials is insufficient, it will directly threaten the stability and safety of production equipment, and may even cause serious production accidents. Therefore, evaluating and improving the high temperature structural strength of refractory materials through scientific methods and accurate data is crucial to ensuring the continuity and safety of industrial production. This can not only provide a solid guarantee for the normal operation of the enterprise, but also lay a solid foundation for the sustainable development and technological progress of the entire industrial field.
PART.06
In short,
High temperature structural strength is one of the key indicators for measuring the performance of refractory materials. Accurately evaluating this indicator by measuring the softening temperature under load and other methods can not only help us understand the performance characteristics of refractory materials, but also provide a strong guarantee for the safe and stable operation of industrial production. I hope the introduction of this article can help you!
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