Steel fiber castable production process and characteristics

1. Production process of steel fiber castables

The steel fibers used for refractory castables generally have a diameter of 0.4-0.5mm and a length of 25mm. The shape and cross-section of the steel fibers are crescent-shaped. The amount of steel fiber added to the castable is 1~5% (weight), and the length and amount of steel fiber should be appropriate.

Generally, water is added to the mixture first and then the steel fibers are added for full mixing. This not only enables the mixture to be stirred evenly, but also saves 1/3 of the mixing time compared to stirring the steel fibers in dry materials. The molding can be vibrated externally, or a vibrating rod can be used to vibrate inside the mixture, and dense products can also be obtained. The maintenance and drying of steel fiber castables are the same as those of ordinary castables.

2. Characteristics of steel fiber castables

1. Steel fiber strengthens the tensile and flexural strength of refractory castables.

2. For castables of the same material, the castables with steel fibers will lose corners after 19 cycles of water cooling at ~1100°C, while the castables without steel fibers will lose corners after 14 cycles. Therefore, it is proved that the use of steel fibers can improve the thermal shock resistance of castables.

3. Steel fiber refractory castables can still bear load even after cracking, thereby improving the fracture work of the castables and increasing the plasticity of the refractory castables.

4. Steel fiber castables can improve the mechanical strength after heat treatment. The use of steel fiber castables can improve the mechanical strength of the castables, especially the mid-temperature strength. The compressive strength can increase by +41% after burning at 1100℃*3h. This is because the castables gain strength from hydraulic products at low temperatures, and the hydraulic bonding is strong at high temperatures. The degree of hydraulic bonding is replaced by ceramic bonding. Therefore, the castables have high strength at low and high temperatures. However, at medium temperatures, the hydraulic bonding strength is lost due to dehydration of the hydration products, and the ceramic bonding has not yet been fully formed. Therefore, steel fibers play an important role at medium temperatures.

At present, more and more departments at home and abroad are applying steel fiber castables. In some hot-working parts that are difficult to withstand with ordinary castables, especially in hot-working parts with frequent thermal shocks and severe impacts, the use of steel fiber castables is very effective.