Light thermal-shield refractory castable

Abstract

The invention relates to a light thermal-shield refractory castable comprising the following components in percentage by weight: 40-60% of light aggregate, 10-20% of capacitance mullite, 5-10% of kyanite powder, 5-10% of high-aluminium clinker powder, 3-8% of silica micro powder, 3-8% of alpha-Al2O3 micro powder, 5-10% of high-aluminium cement, 0.5-10% of high-aluminium refractory fibre containing zirconium, 1.5-4% of thermal-shield steel fibre, 0.1-1% of melamine and 0.05-0.1% of organic anti-explosion fibre, wherein the granularity of the capacitance mullite is less than or equal to 1 mm, both the granularity of the silica micro powder and the granularity of the alpha-Al2O3 micro powder are less than or equal to 5 mu m, and the chemical modified light aggregate is obtained by drying after the light aggregate is dipped in inorganic chemical solution or sol. The light thermal-shield refractory castable of the invention can improve the service life of a furnace roller, lowers production consumption cost, reduces non-working hours caused by exchanging rollers and improves production efficiency.

Description

technical field [0001] The invention relates to a refractory material, in particular to an unshaped refractory material, in particular to a light-weight heat-insulating refractory castable for the furnace roll of a thin slab continuous casting and continuous rolling roller hearth heating furnace. Background technique [0002] Roller hearth heating furnace for thin slab continuous casting and rolling is the connection equipment between thin slab continuous casting machine and thin slab continuous rolling mill. Its working performance will directly affect the normal operation of the entire production line. The task of supporting and driving the slab is the harshest working environment, where the temperature is as high as 1100-1250°C for a long time. The metal roller ring plays the role of supporting and driving the slab, and a fire-resistant and heat-insulating protective layer is laid between the outer wall roller rings to protect the furnace roller, reduce water cooling heat...

AI Technical Summary

Problems solved by technology

Compared with the first type of furnace roller, this kind of furnace roller has a simple manufacturing process, strong resistance to mechanical vibration and flue gas erosion, but there are many problems in the process of use: 1) castable material capacity Significant, it increases the weight of the furnace roller and the power consumption of rotation, and it is easy to crush the roller shaft, shortening the service life of the furnace roller bearing; 2) The furnace roller castable produced by Italy Dexing Company uses calcium aluminate cement As a binder, there is a serious decrease in strength in the medium temperature range of 900-1200°C, which makes the refractory castable more prone to cracking and falling off during the rotation of the furnace roll, resulting in a shorter actual service life of the furnace roll; 3) The used Heavy refractory castables have high thermal conductivity and poor heat insulation performance, resulting in increased heat load on furnace rollers, serious heat loss, fouling on water-cooled wall surfaces, and decreased cooling intensity, resulting in an increase in the average operating temperature of furnace rollers

In view of the above problems, "A Refractory Castable for Roller Hearth Furnace Roller" (authorized announcement number CN100408515C) discloses a kind of refractory castable made of fused mullite, coke gemstone, mullite, cordierite, kyanite, The heavy refractory castable composed of silica micropowder, alumina micropowder, high alumina cement, stainless steel fiber, explosion-proof fiber, sodium tripolyphosphate, and water, by improving the thermal shock stability of furnace roller refractory castable, to a certain extent achieved Improve the effect of cracking and peeling of the castable layer, but there are still shortcomings such as heavy refractory castables with large volume, high thermal conductivity, and poor thermal insulation performance

[0005] From the above-mentioned analysis of the working environment of the furnace rolls of the thin slab continuous casting and continuous rolling furnace rolls and the heat insulation protection layer of the furnace rolls, it can be seen that due to long-term exposure to the roller hearth furnace with a temperature as high as 1100-1250 ° C, the furnace rolls The heat insulation protective layer material must have a certain degree of refractoriness; the O of each section in the furnace 2 and CO content fluctuate in a large range, and the reducing atmosphere will cause the inorganic fiber to crystallize and pulverize at a relatively low temperature, thereby reducing the maximum use temperature of the inorganic fiber material, and the content of water vapor in the inlet section of the furnace is high, and the atmosphere is complex , high-temperature water vapor seriously erodes refractory materials, therefore, the material must have a certain ability to resist high-temperature chemical erosion and flue gas erosion; the inside of the furnace roller passes cooling water, and the temperature difference between the inside and the outside is large, and the material must not only have a small thermal conductivity , reduce the heat loss taken away by the cooling water, have good heat insulation performance, and must also have good thermal shock stability; according to the process requirements and production rhythm, the furnace roller needs to constantly change the speed and rotation direction, and the furnace roller rotates During the process, the heat-insulating refractory castable is not only affected by the rotating centrifugal force, but also by the mechanical impact force generated by the frequent collision and friction between the slab and the roller ring during the rapid travel. Therefore, the material must have a certain resistance to mechanical vibration; furnace The roller rotates through the drive of the motor. If the specific gravity of the heat-insulating refractory castable is too high, the weight of the furnace roller and the power consumption of the rotation will be increased, and the bearing will be easily crushed, which will seriously affect the service life of the furnace roller bearing. Therefore, when meeting other performance requirements Under the premise, the specific gravity of the material should be reduced as much as possible

However, the above two forms of furnace roll heat insulation protection layer are difficult to meet all the performance requirements of the above thin slab continuous casting and continuous rolling furnace rolls, so that the above problems appear in the actual use process

[0006] At present, the refractory and heat-insulating protective layer of the furnace roll of the thin slab continuous casting and rolling roller hearth heating furnace adopts two forms: the method of wrapping the refractory fiber rope with the heat-resistant alloy steel wire inside and spraying the refractory fiber coating, and the method of casting heavy refractory castables. , can not all meet the performance requirements of light bulk density, excellent heat insulation performance, good thermal shock stability, mechanical vibration resistance, flue gas erosion resistance and high temperature chemical erosion resistance that must be possessed in the use of furnace rollers at the same time.

Therefore, in the process of actual use, the former has the disadvantages of complex manufacturing process, high cost, low strength, poor mechanical vibration resistance, high temperature flue gas erosion and high temperature chemical erosion, and low service life; the latter has large capacity. , easy to crush the roller shaft, high thermal conductivity, poor thermal insulation performance and other shortcomings

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