Powdery ferro silicon nitride is mainly used in the plug mud of large blast furnaces, and a small amount is used in iron groove material or other amorphous refractories.
Granular ferro silicon nitride is mainly used for oriented silicon steel or other steels that use nitride to increase strength (such as HRB400 rebar).
Ferro silicon nitride has been widely used in blast furnace blast mud, which greatly improves the plugging property of blast furnace, meets the need of blast furnace iron production, and becomes an indispensable part of modern large blast furnace blast mud. In addition, adding a small amount of ferro silicon nitride to the raw material of the iron ditch greatly increased the iron flux of the iron ditch.
Cannon mud is a kind of carbon bonded refractory material used in blast furnace iron outlet. With the development of large blast furnace and long life, cannon mud has changed from a simple expendable refractory material to a functional refractory material.
The key to the application of ferric silicon nitride in gun-mud is different from silicon carbide and silicon nitride in the presence of ductile particles in ferric silicon nitride, strengthening bulk iron and intermetallic compound ferric silicon, ferric silicon promotes the transformation of each ferric silicon sintered in gun-mud and improves the bonding strength between oxides and non-oxides.
Second, compared with the shot mud with silicon carbide and silicon nitride, the high temperature folding strength of the shot mud is increased to different degrees at different temperatures. In addition, the high temperature of the shot mud can decompose and produce nitrogen, resulting in small dispersed pores in the shot mud, which is conducive to improving the drillability of the shot mud.
Thirdly, with the increase of the amount of ferro silicon nitride in the shotclay, the bending strength at each temperature section increases correspondingly. When the amount of ferro silicon nitride exceeds 24%, the porosity of the shotclay increases obviously, and the bending strength at each temperature section decreases correspondingly.
Fourthly, there is almost no difference in the iron erosion ability of the gun-mud with the addition of silicon carbide, silicon nitride and ferric silicon nitride respectively.
①Fe-Si3N4-SiC composite material
Si3N4-SiC material has good physical and chemical properties, especially high temperature properties, and is widely used in high temperature fields such as blast furnaces and aluminum electrolyzers, and has a good use effect. Compared with pure silicon nitride, ferric silicon nitride has better sintering properties and can be used as high temperature bonding phase. Fe-si3n4-sic composites not only contain high temperature reinforcement phase SiC and silicon nitride, but also contain metal plastic phase (Fe, FeSi or Fe3Si), which can improve the thermal shock resistance of the material, and has a good application prospect in the field of high temperature.
② Other refractory materials
Ferro silicon nitride contains high temperature reinforced phase silicon nitride and metal plastic phase Fe, which has a series of excellent properties such as good high temperature performance, small thermal expansion coefficient, good thermal shock resistance and not easy to be penetrated by slag, etc., and has also been used in other refractory materials. For example, with corundum and spinel as raw materials, adding ferro silicon nitride in the form of fine powder, according to the transition plasticity theory to prepare low-cost anti-oxidation, anti-erosion good chromium-free non-burning refractory. The refractory has excellent physical properties, good oxidation resistance and corrosion resistance of molten steel, and can be used in RH refining furnace instead of magnesium-chromium brick.
In the field of steelmaking, granular ferric silicon nitride was initially used in the production of oriented silicon steel, which can add a certain amount of nitrogen to molten steel stably. At present, the amount of ferro silicon nitride used in the steelmaking field is hundreds of tons a year. In recent years, the progress of smelting technology has made the production of high-strength microalloyed steel develop rapidly, and the strengthening microalloyed elements of steel mainly include vanadium, niobium, titanium and so on.
By calculation and comparison and practical application, the production of HRB400 steel bars using FeV50+ ferric silicon nitride microalloying scheme, alloying cost is reduced by 127.61 yuan compared with the single use of FeV50 tons of steel, compared with the production of VN12 microalloying tons of steel cost is reduced by 44.21 yuan. The use of ferro silicon nitride is of great significance for the production of construction steel enterprises to reduce costs and increase efficiency.
