Construction Methods of Steel Fiber Castables

During the construction of steel fiber castables, attention should be paid to the following four key steps: mixing, pouring, curing, and baking. Failure in any of these steps will lead to deterioration in product performance.

1. Mixing

a. Mechanical mixing: Equipment and tools include: forced mixer, bucket scale, vibrating rod, shovel, wheelbarrow, etc.

b. Construction Water Consumption: Special attention should be paid to water usage. The water content of steel fiber castables should be precisely controlled within a range of 7-8%, which is critical for ensuring construction quality and material performance. The quality of the water used is also crucial. We recommend using potable water for mixing to ensure the purity and stability of the castable, further guaranteeing optimal construction results.

c. Construction Temperature Requirements and Control: The construction of steel fiber castables has specific requirements for ambient temperature. To ensure construction quality and castable performance, the construction site temperature must be strictly controlled within a range of 10-25°C. If the construction site temperature is below 10°C, appropriate heating and cooling measures must be implemented to ensure a suitable construction environment and prevent material performance degradation. Conversely, if the construction site temperature exceeds 30°C, effective cooling measures must be implemented to lower the ambient temperature. Such temperature control is crucial; failure to do so may lead to construction difficulties and even affect the performance of the steel fiber castable. Therefore, we must closely monitor and precisely control the temperature conditions at the construction site.

d. Mixing: The mixing process for steel fiber castables requires meticulous care to ensure maximum material quality. First, the bulk material and the bags are placed in a blender and dry-mixed for 3-5 minutes until all materials are thoroughly incorporated and uniformly mixed. This step is crucial as it lays a foundation for the subsequent addition of water and mixing.

Next, we accurately weigh the required amount of water for each mix, based on the specified water addition amount. The water is then slowly poured into the thoroughly mixed dry material, and the blender is started to mix thoroughly. This mixing process should last at least 1-3 minutes to ensure that the water and dry materials are fully incorporated and that the castable has a certain degree of fluidity. Throughout the mixing process, we ensure every step is precise and accurate to ensure the high quality and stability of the steel fiber castable. This meticulous mixing process allows us to produce steel fiber castables with superior performance, providing a solid material foundation for subsequent construction.

e. Precautions: First, before construction, all tools, such as buckets, mixers, and shovels, must be thoroughly cleaned. These tools must be free of any dirt or debris, especially residues such as Portland cement, to ensure the purity of the construction process and the quality of the final product.

Second, regarding construction water, we must insist on using potable water. Rainwater and mountain spring water are unsuitable for construction due to their uncertain composition and purity, as they may affect the stability and performance of the castable.

Furthermore, the mixing volume should not be excessive. The mixing volume should be appropriately determined based on the actual mixing capacity of the mixer to avoid material waste or uneven mixing that could compromise quality.

Finally, it is important to strictly control water usage during construction. Excessive water can affect the consistency and strength of the castable, so it’s crucial to add water in the specified proportion to ensure quality and effectiveness.

Following these precautions will ensure smooth steel fiber castable construction and ultimately achieve the desired results.

2. Casting

First, before pouring, ensure the work surface is clean and dry. Rusted sections of the kiln body must be thoroughly polished to reveal the natural metal color and then dried. If the kiln is undergoing maintenance, any remaining castable must be completely removed to ensure a perfect bond between the new castable and the base.

Second, pour the newly mixed castable as quickly as possible—generally within 30 minutes—to ensure the castable’s workability and ultimate strength.

During pouring, slowly pour the thoroughly mixed steel fiber castable into the prepared mold. Then, vibrate the mixture evenly with a vibrator. This step is crucial, as it effectively removes air bubbles from the mix and ensures that the castable fills the mold tightly and evenly. During the vibrating process, carefully observe the surface of the castable until it becomes slurry-like and free of visible bubbles.

In addition, several important points require special attention: Once the steel fiber castable loses fluidity during pouring, it has begun to solidify. Do not add water or stir it again to avoid affecting its final strength. The castable should maintain its naturally formed surface after vibrating. Smoothing with tools is not recommended, and sprinkling fine cement powder on the surface to attempt to smooth it is strictly prohibited. For 48 hours after application, especially before the steel fiber castable has fully hardened, any form of impact or vibration must be strictly avoided, as these actions are highly likely to cause cracks and even damage the entire castable.

3. Curing

Curing is an essential step after the construction of steel fiber castables, as it affects the ultimate performance and service life of the castable. After the steel fiber castable has hardened, immediate measures must be taken to protect the castable. A common practice is to tightly cover the surface with plastic sheeting. This step is crucial as it effectively prevents rapid evaporation of moisture, thereby ensuring that the hydration reaction within the castable proceeds fully. In case of extremely high temperatures, we will also need to cover the plastic film with straw bags to further slow heat transfer and moisture loss. During this period, any form of banging or vibration must be strictly prohibited to prevent damage to the hardening castable.

Depending on the hardening process, the castable can generally be carefully demolded after three days. However, demolding does not mean the end of curing; rather, it is an ongoing process. After demolding, we still need to continue covering and protecting the castable to allow it to further stabilize in a controlled environment.

After three days, we can remove the plastic film or straw bags and allow the castable to dry naturally. This process usually takes three to five days, after which the baking process can begin to bring the castable to optimal condition. Throughout the curing process, our goal is to maximize the performance of the steel fiber castable and extend its service life.

4. Baking

Baking, as the final critical step in the steel fiber castable application process, is of great importance. Due to the relatively dense structure of steel fiber castables, we must be extremely careful during baking. Rapid heating is absolutely prohibited, as it can easily lead to thermal stresses within the castable, which can cause cracks and severely impact its performance and service life.

To ensure a safe and effective baking process, a gentle and gradual temperature increase is necessary. This not only helps prevent cracking but also ensures that chemical reactions within the castable proceed fully and evenly. Controlling the baking time is also crucial; it is generally recommended to limit the entire process to approximately seven days. This schedule ensures thorough baking while avoiding quality issues caused by rushing for results.

In general, the baking process requires care and patience. By scientifically and rationally controlling the temperature and baking time, we can ensure that the steel fiber castable performs at its peak performance, providing a solid foundation for subsequent use.

In industrial production, selecting high-quality refractory materials is key to ensuring stable, efficient, and safe production. Steel fiber castables, with their excellent flexural (tensile) strength, thermal shock resistance, impact resistance, and wear resistance, are becoming the preferred choice of an increasing number of industrial enterprises.