A lightweight thermal insulation castable for the permanent layer of the tundish

Abstract

A lightweight thermal insulation castable for the permanent layer of the tundish, its raw materials and wt% are: mullite aggregate of 8mm≤grain size≤12mm: 5~25%, mullite aggregate of 8<grain size≤5mm: 5~25%, 5<grain size≤3mm mullite aggregate: 5~25%, 3<grain size≤1mm mullite aggregate: 5~15%, 1mm<grain size≤0.074mm mullite aggregate Stone: 5~15%; mullite powder with particle size <0.074mm: 5~15%, hollow ball with particle size 3 to 1mm: 5~15%, hollow ball with particle size<1mm: 5~15%, particle size≤0.02 mm silica powder: 3~6%; alumina powder with particle size ≤0.03mm: 3~6%, andalusite powder with particle size ≤0.074mm: 5~10%, calcium aluminate cement: 3~5%; three Sodium polyphosphate: 0.05~0.1%, polycarboxylate high-performance water reducing agent: 0.05~0.1%, steel fiber: 1~3%, plus 5~7% water of the total weight of the above raw materials. The invention has the advantages of light weight, heat preservation and energy saving, good thermal shock resistance performance, etc., can increase the temperature of molten steel by more than 5°C, lower the temperature of the shell of the tundish steel structure by more than 20°C, improve the quality of cast billets, save energy and reduce consumption.

Description

technical field [0001] The invention relates to a refractory material, which specifically belongs to a refractory material for a tundish, and more precisely is an insulating castable for a permanent layer of a tundish. Background technique [0002] With the advancement of continuous casting technology, in addition to storing and distributing molten steel, the tundish has multiple refining functions such as separation of inclusions and alloying. The structure of the tundish consists of the steel shell of the tundish, the heat insulation layer, the permanent layer and the working layer from the outside to the inside. Clay bricks or nanofiber boards are used for the insulation layer, high-alumina castables are generally used for the permanent layer, and magnesium smear or dry materials are used for the working layer. [0003] At present, the permanent layer of the tundish adopts ordinary high-alumina castables with relatively high density. Due to the high density of this casta...

AI Technical Summary

Problems solved by technology

[0003] At present, the permanent layer of the tundish adopts ordinary high-alumina castables with relatively high density. Due to the high density of this castable, it is generally 2.7g / cm 3 Left and right, resulting in the following deficiencies: First, the steel structure and mechanical devices bear a large load, that is, when the tundish is lifted in a hot state or in the process of pouring steel on the continuous casting platform, the tundish is affected by high temperature, and the tundish The strength of the steel structure decreases, and the mass of the refractory lining of the tundish using ordinary castables is too large. Under the influence of the above two factors, the steel structure of the tundish is more easily deformed, and it is easy to cause deformation of related structural parts; the second is its large specific heat capacity , high thermal conductivity, poor insulation effect

The invention also added too many hollow spheres, resulting in low material strength. After drying at 110°C for 24 hours, the strength was 7.5MPa, and the compressive strength was 15MPa after firing at 1300°C. It is not suitable for high strength and good thermal shock resistance. The tundish permanent layer