Tangshan medium and heavy plate co., ltd. has a plate production capacity of 3 million t / a, steel plant main equipment: 120 t converter 3, 120 tlf refining furnace 2, caster 4, with a higher level of automation control system, can produce thickness of 180,220,250 mm, width of 1600 ~ 2100 mm medium and heavy plate billet.
Molten steel temperature control has a great influence on steel-making cost, and the effect of heat preservation directly affects the temperature of molten steel. The general insulation measures are to use high density ceramic fiber board on the ladle, such as 160t ladle of Panzhihua iron and steel co., ltd. using refractory fiber insulation tile, the thickness of the product is 25 ~ 30 mm, reduce the ladle shell temperature 71 ℃, steel water temperature drop rate decreased by 0.3 ℃ / min. The thickness of the heat insulation tile is too large, occupies the space of the permanent lining castable, and is easy to be compressed to cause shrinkage crack of the permanent lining castable, thus affecting the safe operation of the ladle. Anyang steel 100t steel ladle adopts a new nano heat insulation board with energy conservation and environmental protection of 2m, two layers are used at the bottom of the ladle and three layers are used at the wall of the ladle, the thickness of each layer is 10 mm, so that the total thickness of the heat insulation layer is 20 - 30 mm, and the effect of improving the temperature of molten steel and reducing the temperature of the shell is achieved. According to the data, the composite reflective thermal insulation board ( hereinafter referred to as reflective thermal insulation board ) used in China is a nano oxide powder thermal insulation material, which is used in 40t ladle and 90t ladle of Jinan iron and steel group. the thermal insulation thickness is 20 ~ 25 mm, and the effect of reducing the shell temperature by 33 ~ 78 ℃ is obtained. Similarly, the reflective insulation board occupies too much space of castable thickness, and there is also a hidden danger that the insulation layer is easy to compress and the permanent lining castable shrinks and cracks.
In order to improve the insulation effect of 120 t steel ladle in Tangshan medium and heavy plate co., ltd. and avoid the hidden danger of cracking of permanent lining castable due to the use of too thick insulation layer, steel mills have adopted 7 mm thick reflective insulation plate on 120 t steel ladle. in practical production application, because the thickness of the reflective insulation plate insulation layer is too thin, the insulation effect is not ideal, and the water temperature drop rate of steel is still very large.
A new type of nano heat insulation board was successfully applied in 100t steel ladle of Angang group. the thickness of the product is 7 mm. after 3 years of production practice, good energy saving effect was obtained. the temperature of ladle shell decreased by 33 ~ 52 ℃, the temperature drop rate of molten steel was reduced by 0.21 ℃ / min. no shrinkage cracking occurred in the castable and the service life of the castable for permanent lining was not affected. Therefore, in order to further improve the insulation effect of 120 t steel ladle, Tangshan medium and heavy plate co., ltd. steel plant adopted the new type of nano heat insulation board in Germany, successively in the steel ladle, tundish and converter lining series of comparative experiments, and confirmed the whole steel-making system using nano heat insulation board after the insulation effect.