What is long water mouth

When molten steel is poured from the ladle to the tundish, in order to avoid oxidation and splash, a long water port is installed at the lower end of the sliding water port at the bottom of the ladle, one end is connected to the water port, and the other end is inserted into the molten steel of the tundish for sealed protection pouring. The functions of the long water mouth are as follows:(1) to prevent the secondary oxidation of molten steel and improve the quality of steel;(2) to reduce the oxidation products of the easily oxidized elements in the steel on the inner wall of the nozzle and prolong its service life;(3) the long water mouth can be used many times to reduce the consumption of refractory materials.
The long water outlet shall have the following properties:
(1) Excellent thermal shock resistance;
(2) Good mechanical properties and anti-vibration ability;
(3) good resistance to corrosion of molten steel and slag;
(4) The edge joint must be equipped with an air seal device. The material of the long water mouth is generally fused quartz and aluminum carbon two categories.
Fused quartz long water mouth, the use of slurry casting method, which is characterized by good thermal shock resistance, high mechanical strength and acid slag erosion resistance, good chemical stability. However, it is easy to form low melts with oxides such as iron and manganese in molten steel or slag, and quartz reacts with carbon at high temperatures to be decomposed and gasified, which has poor corrosion resistance and is not conducive to smelting clean steel.
High purity raw materials are selected for aluminum carbon long water mouth to reduce impurity content, improve organizational structure and corrosion resistance according to reasonable particle gradation. Adjust the content of natural graphite and use the non-wettability of coarse-grained flake graphite to steel liquid to reduce nodulation at long water mouth. Improve modeling to reduce nozzle cracks; Application of micropowder technology, adding appropriate amount of Al2O3 micropowder to enhance high temperature strength and thermal stability. The aluminum carbon nozzle has good thermal shock resistance and strong adaptability to steel grades. In order to prevent the carbon on the nozzle surface from being oxidized during baking and use, the nozzle surface is coated with an anti-oxidation coating. The anti-oxidation coating is mainly composed of feldspar, quartz, clay and other raw materials. It is made of glaze by wet grinding and applied to the nozzle surface by artificial or mechanical methods. This coating forms a glaze layer in the range of 700~1000 ℃, so as to protect graphite from oxidation or little oxidation.