Characteristics of Steel Fiber Refractory Castable

July 06, 2018

The steel fiber refractory castable is a heat resistant steel fiber added to the refractory aggregate (refractory aggregate, powder and binder). It can provide the overall performance of the refractory castable, with high strength, good toughness, strong thermal shock resistance and anti-stripping.

Product description

The heat-resisting steel fibers used for the steel fibre refractory castables shall be selected according to the conditions of use of the thermal equipment and determined its proper use. The preparation process: firstly weigh the refractory aggregates, powder, binders and additives, dry mix for 1 min followed by wet mixing, and  spread the steel fibers into the materials evenly, do not clump,finally mixed with 1 min, then can be out of materials.

The total time is not less than 5 min when vibrating rod is used for molding, the vibration direction should be staggered, so that the distribution of the steel fiber can be reasonable and the performance can be improved.

Steel fiber refractory castable application

It’s mainly used in industrial grade furnaces where fire resistant material are required to have good resistance to spalling and impact resistance. For example, cement rotary kiln, heat-resistant steel chain of wet rotary kiln, cement kiln cooling machne, cement kiln coal injection pipe etc.

From the point of view of reinforcement and fire resistance,high strength refractory castables are usually made of heat resistant steel fiber and alumina fiber.

Steel fiber refractory castables type

The varieties of steel fiber refractory castables can be divided into high strength steel fiber refractory castables and high strength alumina fiber refractory castable, characterized by high strength, good toughness, thermal shock resistance and good spalling resistance, and in the heat treatment furnace,heating furnace,soaking furnace,turdish slag,furnace refining and catalytic cracking equipment and other key parts of the furnace and thermal equipment, has been applied to obtain a good technical economic effect. Through many experiments and production at home and abroad,it proves that in any kind of refractory castable, refractory plastic and refractory ramming mass, heat resistant steel fibers with a mass of 1% to 5% can achieve the effect of strengthening and toughening.However, heat-resistant steel fiber have lower melting temperatures and critical oxidation temperatures and should not be used at high temperatures. Otherwise,due to the melting and oxidation of steel fibers,the structure of the surface castable will be damaged or destroyed, resulting in the decline of service life of kiln or thermal equipment. 

The role of steel fiber in refractory castables

The main functions of adding steel fiber to refractory castables include: 1.enhanced toughness, improved stress-resistance and improved mechanical impact resistance. 2.improved thermal shock resistance and improved resistance to cracking and exfoliation. 3.Inhibition linear shrinkage after curing, drying and heat treatment. The addition of steel fiber is generally suitable for 0.6~2.5%(volume ratio).

The refractory aggregate and powder used for steel fiber refractory castable are made of three grade and first grade bauxite clinker. In order to improve the matrix properties, fused alumina powder was added, and activated SiO2 ultrafine powder and additives were added. CA-50 cement is used as coagulant.

Calcium aluminum cement alumina-magnesia refractory castable, dense fused corundum as aggregate, alumina and high-purity sintered magnesium as refractory powder,superfine powder and compound admixture.

Low-cement bauxite-mullite refractory castable,refractory aggregates are made of primary soil clinker and mullite, refractory grades are premium bauxite clinker or corundum, and binder is CA-70 cement,which adding ultrafine powder and composite admixtures. No.5 is a low cement concrete corundum refractory castable with a small amount of admixture added. This type of high quality refractory castable is used at higher temperatures. Therefore,the grade 330 heat resistant steel fiber is selected. The equivalent diameter is 0.5mm and the length is 20mm. The dosage is 2%,and the water dosage is 6% to 7%. According to the mixing ratio of the screening, various raw materials are weighed and molded after mixing.

After molding, it should be naturally maintained without watering. After curing for 24 hours, the mold was removed and the natural curing was continued for 48 hours to check the performance.

refractory castable