Steel is packed is the indispensable container in steelmaking process. As the ceaseless development of steel-making technology, especially the processing of LF of the fine outside furnace and RH, its action from the simplest fill the forge that receives molten steel to develop to have certain smelt function. Molten steel stays for a long time in steel to pack in, inevitably meeting causes the loss of molten steel temperature, the gasket with tall heat conduction can bring about aggravate of molten steel heat loss due to radiation, the steel crust that pack is out of shape more serious, reduced rate of molten steel temperature increases, cause serious slag suspension. Knot tumour. Cooling steel. Cross low temperature, force even irrigate finally build irrigate finally build, affect billet quality not only, and rate of gains of influence molten steel is low, and raised manufacturing cost. Accordingly, insulation steel is packed more and more the demand that makes steelworks. Mode of structure of the insulation steel wear that pack is light normally insulation board or accept rice board + permanent layer is irrigated build material + stuff of working layer wear. The warming plate itself that has heat preservation effect needs a fireproof material to protect lukewarm material not to get too great pressure, 2 it is to protect insulation material not to use temperature more than (if must be under 1000 ℃ ) , so steel wraps permanent layer to irrigate building material is this kind of important material. Heat resistant material should have ideal permanent layer good thermal stability. Heat preservation. Corrosion resistance, use on the safe side, the structure is whole, service life is long. Pack good heat preservation performance to maintain steel, reduce molten steel lukewarm drop, new-style CA6 is irrigated build material and light qualitative Molaishi to irrigate built material to undertake function is evaluated respectively, apply Yu Gang to pack, achieved result of better integrated heat preservation. 1. Experiment process. Current, steel packs permanent layer material to be more common tall aluminium is pouring makings, main raw material is aluminous earth. Fireproof material is using this kind of indeterminate form the following defect exists in the process: It is thermal conductivity tall, energy loss is caused in use process; 2 it is fireproof sex low. If working layer is used unusual, when molten steel contacts permanent layer directly, probability of steel of the leakage that wear a bag is high, safety factor is low; 3 it is bulk density big, weight of steel bag empty bag is great. Accordingly, not contented steel packs the special requirement of heat preservation, need develops new-style integral performance exceedingly good permanent layer is pouring makings. The article is pouring to new-style CA6 makings and light qualitative Molaishi are pouring makings had sample and test. 1) raw material reachs test program. Main raw material and its chemistry composition see a table 1.
Express 1: The chemical composition of main raw material. Among them CA6 raw material (CaAl12O19, is logogram CA6) be CaO-Al? O? The Al in the department? O? The aluminous acerbity calcic photograph with highest content, its melting point 1875 ℃ , is hot coefficient of expansion ℃ of 8 × 10-6? ? , is the bulk density of grain 2.70g · Cm? ? , apparent pore is led 26.8% . Should expect fireproof function and board shape corundum are similar, and the 1/3 that coefficient of thermal conductivity has corundum only, be in recent years raw material of a arisen kind of new-style and high grade heat preservation. CA6 is pouring makings it is aggregate with CA6, matrix part uses board shape corundum fine pink, alumina pink and cement of aluminous acerbity calcium are made for bond. Is the bulk density of grain of globose light qualitative Mo Laishi 1.59g · Cm? ? , apparent pore is led 38.9% . Light qualitative Molaishi is pouring expecting is the M70 that uses small Kong Hua the ball is globose light qualitative Molaishi aggregate, matrix part uses board shape corundum fine pink, alumina pink and cement of aluminous acerbity calcium are made for bond, in order to assure the better aggressivity that fight broken bits can, in order to enhance the security of permanent layer. 2) checks process and function test. Pouring two kinds pouring after makings, undertake physical function experiment is mixed respectively anti-corrosive experiment. Physical experiment method presses national level or occupation standard method undertakes. 2. Material function result reachs an analysis. 1) physics function. From the watch 2 can see, different steel wraps permanent layer pouring the function of makings is different.
Express 2: Steel wraps permanent layer pouring the physical function of makings. Light qualitative Molaishi is pouring makings bulk density is 2.17gcm, sheet compares the tall aluminium that uses at present again pouring stuff is low 24% , thermal conductance falls 16% , can obtain steel the parcel is small quantify, the end with low coefficient of thermal conductivity. CA6 is pouring makings also compare common tall aluminium is pouring makings is light 5.6% , thermal conductance is reduced 26% . 2) is anti-corrosive experiment. B. New-style CA6 is irrigated irrigate build material B. New-style CA6 is irrigated build material C. Light qualitative Molaishi is irrigated build material 3# to be irrigated respectively build crucible. Below the condition of 3h of 1500 ℃ heat preservation, join converter final broken bits, undertake crucible anti-corrosive experiment. Watch different stuff be able to bear or endure fusibility and osmotic. After the experiment is finished, crucible by cut. Corrode a circumstance to see figure below 1:
Note 1: Commonly used tall aluminium is pouring makings.
Note 2: CA6 is pouring makings.
Note 3: Light qualitative Molaishi is pouring makings. Graph 1: ? Heat preservation of ℃ of?500 of v/LIT all over the ground principle columns of a hall of peak Zhui good section plane photograph of 3 hours. CA6 is pouring makings have first-rate corrosion resistance and osmotic, the rest inside crucible aperture is many broken bits; Next, light qualitative Molaishi is pouring makings have corrosion resistance and osmotic; Common tall aluminous permanent layer is pouring makings broken bits and fireproof material border are not clear, crucible is fireproof material and broken bits are fused, be able to bear or endure osmotic slightly good at corrosion resistance, explain tall aluminium is pouring below 1500 ℃ makings fluid look is more, because this needs to raise its high temperature resistant quality, the security that this includes to steel is very important. The small Kong Hua of globose light qualitative Molaishi is helpful for rising corrosion resistance and osmotic, because this pledges gently,material also can behave heat preservation and corrosion resistance better. 3. Application. Above is irrigated 3 kinds build material application to be packed at 300t steel. Insulation steel packs permanent layer to pledge Molaishi is irrigated gently build material. It is good that CA6 irrigates the target that builds material to ask be able to bear or endure molten steel aggressivity and insulating properties, integrality of furnace craft structure is good. Insulation effect is stable. Different steel packs the exterior condition of permanent layer to see the following picture:
Graph 2: Application is different and permanent the layer is pouring the photograph after makings 300t steel is wrapped. Afore-mentioned steel wrap permanent layer to appear in furnace battle later period the crackle of different level, the heat of this and material brace up gender, intensity and disassemble the attaint in the process is concerned. The integrated technology that how reduces heat preservation steel to wrap craze of permanent layer material still needs to be deepened further. From the point of the average temperature of every slag line, the steel casing that does not have line of heat preservation slag is in 320 ℃ above, and the average temperature of the line of broken bits of 4 experiments bag that introduces heat preservation is under 280 ℃ , the steel casing temperature of line of general broken bits drops 50~100 ℃ . According to the different configuration of insulation material and permanent layer material, the steel casing temperature of wall body place drops between 20~50 ℃ , somewhat difference. The insulation material that heat preservation experiment includes in furnace battle period keeps good, broken bits line. The average temperature of casing of wall body steel is wrapped under common steel, show permanent layer produced favorable protective effect. To assure safety, new permanent layer material still needs to optimize after two furnace battle improve, in order to ensure applicable at 4 furnace battle. 4. Conclusion. Heat preservation steel is packed already became steely company the main technique measure of energy-saving environmental protection. Steel packed permanent layer material to raise taller requirement. The CA6 of development irrigates qualitative Molaishi pouring the applied requirement that the intensity of makings accords with steel to pack permanent layer. In the meantime, they are more pouring than traditional tall aluminium the heat preservation that expects it is better to have and corrosion resistance, can protect insulation material, make steel packs the heat preservation that keeps good during furnace battle. The integrated technology that reduces heat preservation steel to pack craze of permanent layer material needs to be deepened further.
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