Casting method of cast steel rotary furnace flue

Abstract

The invention relates to a casting method of a cast steel rotary furnace flue, which adopts a cast steel to cast a base body and a cooling water pipe. The casting method comprises the following steps: adding a slagging agent and a silicon iron alloy block in molten steel for casting steel; putting the cooling water pipe into a casting model and leading a liquid cold medium and a composite solid cooling medium to pass through the cooling water pipe; using molten steel for casting steel to cast the base body; leading the casting model to be horizontal in the modeling process, leading a feeder head to be modeled lopsidedly toward one side and heightening one side of the feeder head of the model after the model is boxed; adopting an upper layer of inner sprue and a lower layer of lower sprue to carry out stepped casting so as to form sequential solidification; and cooling and disassembling the model. The casting method can effectively avoid the cooling water pipe from being penetrated in a fusing manner during the casting process, avoids air gaps from being generated between the base body and the cooling water pipe, avoids refusion and recrystallization, accurately realizes the microfusion of the outer surface of the cooling water pipe, prolongs the service life of the rotary furnace flue, further prolongs the service life of a metallurgical high-temperature kiln, saves production cost and improves the mechanical performance of the cast steel rotary furnace flue.

Description

technical field [0001] The invention relates to a metallurgical high-temperature furnace, in particular to a casting method for a cast steel converter flue of a metallurgical high-temperature furnace, belonging to the technical field of metallurgy and ironmaking. Background technique [0002] The converter flue is a device that provides cooling for metallurgical high-temperature furnaces. It can protect the furnace shell of metallurgical high-temperature furnaces from erosion and mechanical wear of high-temperature fluids in the furnace body, prolong the life of metallurgical high-temperature furnaces, and ensure their safe and stable production. Once there is a problem with the cooling equipment, the metallurgical high-temperature furnace must be completely shut down for maintenance, which will cause major economic losses. Therefore, the life of the converter flue determines the life of the metallurgical high-temperature furnace, which is an important guarantee for the long...

AI Technical Summary

Problems solved by technology

Taking the most widely used ductile iron converter flue as an example, it has the following disadvantages: (1) The ductile iron converter flue must be equipped with an anti-carburization coating outside the cooling channel, so that an air gap is formed between the channel and the substrate, and the gas The gap makes the heat transfer resistance of the converter flue significantly increased, which deteriorates the heat transfer effect of the converter flue, increases the temperature of the working surface of the converter flue, and accelerates the damage of the converter flue; (2) the ductile iron matrix is ​​covered with spherical graphite of different sizes ( Particle size 0.025~0.150mm), spherical graphite is equivalent to forming countless tiny holes after being oxidized, which constitutes the birthplace of cracks and cracks, accelerates the expansion of cracks and cracks, and shortens the service life of the converter flue. Increased resource consumption is not conducive to the longevity and energy saving of the converter flue; (3) When casting large ductile graphite castings, C, S, and P are easily pushed to the liquid region during the columnar crystallization process, forming a segregation rich in the central equiaxed crystal region. There is a large difference in the elongation between the surface and the center of the casting, and the surface elongation is more than twice that of the center, which promotes the generation and expansion of cracks or cracks in ductile iron, which is not conducive to the longevity of the converter flue; (4) ductile iron The linear expansion coefficient changes relatively steadily below 600°C, but above 600°C, a sharp irreversible "growth" occurs with the increase of temperature. When the temperature is greater than 709°C, the matrix structure undergoes phase transformation, and the expansion coefficient and internal stress (5) The thermal conductivity and thermal shock resistance of ductile iron are poor, and its thermal conductivity is only 30w m -2 ·K -1 , which is not conducive to the efficient cooling of the converter flue

Simply considering it from a certain angle cannot solve the problem very well, and it needs to conduct systematic research on the basic principles of interdisciplinary and multidisciplinary

Due to the above limitations, the current application of cast steel in the converter flue still cannot meet the requirements of industrial applications

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