TItle：What are the main physical and chemical properties of continuous casting mold flux?
Description：After the mold flux is prepared, the physical and chemical properties of the slag must be measured. This article points out the main physical and chemical indicators of continuous casting mold flux
After the protective slag is prepared, the physical and chemical properties of the slag should be measured. The main physical and chemical indicators are as follows:
(1) Chemical composition: The chemical composition of the mold powder of each brand should be analyzed, and the content of each oxide should be within the specified range. This is the minimum index.
(2) Melting temperature, the slag powder is made into a sample of Φ3×5mm, and the sample is heated on a special instrument to the temperature at which the cylinder becomes hemispherical. The temperature at which the hemispherical point is reached is defined as the melting temperature.
(3) Viscosity: It represents the fluidity of slag powder melted into liquid. The fluidity of the slag has an important influence on the slag absorption of inclusions and the lubrication effect of the blank shell. The viscosity of the slag at 1300°C is usually measured with a torsion viscometer or a rotational viscometer to compare the fluidity of different slags.
(4) Melting speed: The melting speed is a measure of the speed of the slag melting process, which is related to whether a stable three-layer structure can be formed on the liquid surface of the mold steel and the required thickness of the slag layer.
The melting rate can be expressed by the time it takes for a standard sample to completely melt into a liquid at a specified temperature (such as 1300°C or 1400°C). It can also be expressed by a certain weight of protective slag powder, heated to a specified temperature, and the amount of liquid slag formed per unit area and time.
(5) Spreadability: It represents the covering ability and covering uniformity of the powder slag added to the molten steel surface. It can be measured by the area of mold powder in a certain volume, which flows down from the specified height to the flat plate.
(6) Moisture: The protective slag powder is easy to absorb moisture. If the amount of adsorbed water exceeds the specified requirements (such as 0.5%), the slag powder will agglomerate, endangering the use effect。