Analysis and control of serious intrinsic quality defects of fused cast AZS sidewall blocks

· Improper raw material ratio:
During the melting and casting process, the ratio of raw materials directly affects the composition distribution and crystal structure inside the block. If the raw material ratio is improper, it will lead to uneven distribution of components inside the block, which will affect the perfection of its crystal structure. 

This uneven distribution of components will make the block more prone to cracking and peeling under physical and chemical effects.

· Unreasonable control of melting and casting temperature and cooling rate:
Melting and cooling rate are key factors affecting the crystal structure of blocks. If the melting and casting temperature is too high or the holding time is too long, the grains inside the block will be too large and the structure will be loose. If the cooling rate is too fast, it will cause excessive thermal stress inside the block, which will cause cracking and peeling.

· Too high porosity:
Similar to glass phase seepage, too high porosity is also one of the important reasons for loose structure. High porosity will reduce the overall strength and corrosion resistance of the block, making it more prone to cracking and peeling under long-term high-temperature operation.

1.3 Uneven composition

Uneven composition is one of the inherent quality defects of fused cast AZS sidewall blocks, which is mainly manifested in the large difference in chemical composition of different parts inside the block. This uneven composition will lead to a decrease in the corrosion resistance and thermal shock stability of the block, thereby affecting its service life.

The main reasons for uneven composition include:

· Uneven mixing of raw materials:
Before melting and casting, the mixing uniformity of raw materials has an important influence on the composition uniformity of the block. If the raw materials are not mixed evenly, the chemical composition of different parts in the melting and casting process will be greatly different, which will affect the overall performance of the block.

· Insufficient stirring during melting and casting:
During the melting and casting process, the sufficiency of stirring directly affects the composition distribution inside the melt. If the stirring is insufficient, the composition distribution inside the melt will be uneven, which will affect the composition uniformity of the block.

· Unreasonable control of melting and casting temperature and holding time:
The melting and casting temperature and holding time have an important influence on the uniformity of the melt and the diffusion of the composition. If the melting and casting temperature is too high or the holding time is too long, it will cause uneven diffusion of the components inside the melt, which will in turn affect the uniformity of the composition of the block.

1.4 Bubbles and cracks

Bubbles and cracks are common appearance defects of fused cast AZS sidewall blocks, but they will also affect their internal quality. The presence of bubbles and cracks will reduce the strength and corrosion resistance of the block, thereby shortening its service life.

The main causes of bubbles and cracks include:

· Incomplete gas discharge during melting and casting:
During the melting and casting process, if the gas is not completely discharged, bubbles will form inside the block. These bubbles will not only reduce the mechanical properties of the block, but also become areas of thermal stress concentration, increasing the risk of cracking.

· Unreasonable control of melting and casting temperature and cooling rate:
Similar to loose structure, unreasonable control of melting and casting temperature and cooling rate will also cause excessive thermal stress inside the block, thereby forming cracks. In addition, uneven cooling rate will also cause residual stress inside the block, further aggravating the formation of cracks.

· Impurities or bubbles in the raw materials:
If the raw materials contain impurities or bubbles, they will be brought into the block during the melting and casting process, forming defects.

Ⅱ. Control measures for the intrinsic quality defects of fused cast AZS sidewall block

For the intrinsic quality defects of fused cast AZS sidewall block, the following control measures can be taken to improve their quality stability and reliability:

2.1 Optimizing the raw material ratio and mixing process

Optimizing the raw material ratio and mixing process is one of the important measures to control the intrinsic quality defects of fused cast AZS sidewall block. By reasonably proportioning the raw materials, the uniformity and stability of the internal components of the block body can be ensured. At the same time, the use of advanced mixing processes can improve the mixing uniformity of the raw materials and avoid the problem of uneven composition.

► In terms of raw material ratio, the appropriate raw material types and ratios should be selected according to the operating conditions and requirements of the glass melting furnace. At the same time, factors such as the particle grading and shape of the raw materials should also be considered to ensure the fluidity and uniformity of the melt during the casting process.

► In terms of mixing technology, efficient mixing equipment and technology should be used to ensure the full mixing and uniform distribution of the raw materials. At the same time, the mixing uniformity of the raw materials can also be ensured by optimizing parameters such as mixing time and mixing intensity. In addition, the mixing equipment should be inspected and maintained regularly to ensure its normal operation and mixing effect.

2.2 Controlling the melting and casting temperature and cooling rate

Controlling the melting and casting temperature and cooling rate is one of the key measures to control the intrinsic quality defects of the fused cast AZS sidewall blocks. The melting and casting temperature and cooling rate directly affect the crystal structure and performance of the block body.

► During the melting and casting process, the melting and casting temperature and holding time should be reasonably controlled according to the characteristics of the raw materials and the capacity of the melting and casting equipment. During the cooling process, a reasonable cooling method and speed should be adopted to avoid excessive thermal stress and cracks inside the block body. For example, a segmented cooling method can be adopted, first cooling to a certain temperature range at a faster speed, and then continuing to cool to room temperature at a slower speed; at the same time, forced convection or natural convection can also be used to improve cooling efficiency and reduce thermal stress.

► In addition, the melting and casting equipment should be inspected and maintained regularly to ensure its normal operation and melting and casting effect. For example, the slag and impurities in the melting furnace should be cleaned regularly to avoid contamination and influence on the melt; at the same time, the melting temperature controller and cooling system should be checked and calibrated regularly to ensure their accuracy and stability.

2.3 Optimizing sand mold process and pouring method

Optimizing sand mold process and pouring method is one of the important measures to control the intrinsic quality defects of fused cast AZS sidewall blocks. Sand mold process and pouring method directly affect the appearance quality and intrinsic quality of blocks.

► In terms of sand mold process, appropriate sand mold materials and molding methods should be selected according to the size and shape of the blocks. At the same time, appropriate factors such as sand mold compactness and air permeability should be selected to ensure sufficient filling and good crystallization of the melt. During the pouring process, the pouring speed and temperature should be reasonably controlled to ensure that the melt fully fills the sand mold and forms a good crystal structure. For example, the preheating sand mold can be used to improve the filling efficiency of the melt and reduce thermal stress;

► In addition, the monitoring and management of the sand mold and pouring process should be strengthened. For example, the sand mold should be inspected and cleaned regularly to avoid contamination and influence on the melt; at the same time, the monitoring and recording of the pouring process should be strengthened to timely discover and solve problems.

2.4 Strengthen quality inspection and monitoring

Strengthening quality inspection and monitoring is one of the necessary measures to control the inherent quality defects of fused cast AZS sidewall blocks. By regularly inspecting and monitoring the appearance quality and internal performance of the block body, problems can be discovered and solved in time to ensure the stable and reliable quality of the block body.

► In terms of quality inspection, advanced inspection technology and equipment should be used to conduct comprehensive inspections on the appearance quality, dimensional accuracy, chemical composition, physical properties and corrosion resistance of the block body. In terms of monitoring, a complete quality monitoring system should be established to monitor and record all links in the melting and casting process in real time.

► In addition, the training and management of quality inspection personnel should be strengthened. For example, quality inspection personnel should be trained and assessed regularly to improve their inspection skills and level; at the same time, the supervision and management of the quality inspection process should be strengthened to ensure its accuracy and reliability. The quality problems found should be handled in a timely manner, and the implementation of improvement measures and tracking and verification of the results should be carried out.

Ⅲ. Conclusion

The inherent quality defects of fused cast AZS sidewall blocks are important factors affecting their performance and life. 
      ⇒   By optimizing the raw material ratio and mixing process

         ⇒   Controlling the melting temperature and cooling rate

         ⇒   Optimizing the sand mold process and pouring method

         ⇒   Strengthening quality inspection and monitoring

the inherent quality defects of fused cast AZS sidewall blocks can be effectively controlled and their performance and service life can be improved. At the same time, these measures also provide useful reference and reference for related production and application.

In future research and application, the production process and quality control method of fused cast AZS sidewall blocks should be further explored and optimized to continuously improve their quality and performance level to meet the operating requirements of glass melting furnaces and the market demand for glass products.

 Henan SNR Refractory Co., Ltd. has been specializing in the production of fused cast AZS blocks for about 25 years. We use high-quality raw materials and advanced fusion technology to provide customers with high-quality products. From raw material procurement to finished product delivery, every step is strictly quality inspected to ensure that every indicator meets the standards, so you can use it with confidence.

If you have any needs, you can contact me at any time.

Web:www.snr-azs.com

Email:wendy@snrefractory.com