Luoyang Turner High Temperature Instrument Co., Ltd., Ltd.

1

Testing principle and selection of melting point and melting rate tester

Melting point is the equilibrium temperature of a solid and liquid substance under atmospheric pressure. It is measured by the temperature increase of a crystalline substance from solid to liquid and is recorded as the melting point. Melting point is an important method for identifying substances and determining the purity of substances. Therefore, melting point apparatus plays an important role in the chemical industry and medical research. Pure solid substances generally have a fixed melting point and a short melting range, generally not exceeding 0.5-1℃, which can be used to determine the purity of the substance and identify unknown substances. Mix the unknown substance with a known substance and measure the melting point. If the melting point does not change and the melting point range does not exceed 1℃, it can usually be considered that the two are the same substance. This method is called the mixed melting point method. At this stage, the main method for testing the melting point is to use a melting point apparatus for measurement. The manufacturing standard of the melting point apparatus is the national standard JJG 701-2008 verification procedure. Melting point apparatus is popular with users for its simple operation and clear results, especially fully automatic melting point apparatus does not require laboratory personnel to monitor at any time. Currently, there are many types and brands of melting point apparatus on the market. The following aspects can be referred to when selecting a suitable melting point apparatus: 1. Testing conditions of the sample: Powder samples can use a melting point apparatus based on capillary melting point measurement method, which can

2022

Functions of continuous casting slag protection

In the continuous casting process, after the continuous casting flux is added to the mold, it is heated and sintered and melted on the steel surface to form a liquid slag layer. When the mold powder near the liquid slag layer does not reach the melting temperature, it has been sintered into a transition layer. Above the transition layer is the original slag layer. This is the three-layer structure of the tundish powder that we usually call—liquid slag layer, sintered layer, and original slag layer. The liquid slag and liquid steel together form a meniscus near the crystallizer wall. Under the action of crystallizer vibration, gravity, and capillary adsorption, the liquid molten slag flows into the gap between the crystallizer wall and the billet shell through the meniscus to form a slag film. The consumption of the liquid slag pool and liquid slag on the steel surface between the crystallizer wall and the billet shell forms a dynamic equilibrium. The functions of continuous casting flux are introduced below: 1. Heat insulation to reduce heat loss of molten steel The continuous casting flux used for continuous casting must have good heat insulation properties, which can inhibit the formation of bridges and crusts in the crystallizer during continuous casting, increase the meniscus temperature, make the shell grow stably at the meniscus, and make the radius of curvature of the meniscus large. With the increase of the radius of curvature of the meniscus, the bubbles and oxide inclusions floating from the molten steel at the bottom of the crystallizer are not easily captured by the meniscus, and it is easier to float to the liquid slag layer, making the molten steel cleaner. 2. Isolate air to prevent secondary oxidation

2023

The influence of the melting point of continuous casting slag protection

The thickness of the protective slag layer is related to the consumption of continuous casting slag. The lower the viscosity of the continuous casting slag, the higher the flow rate, the better the lubrication effect on the slab, and the higher the melting speed required. Even in the same mold, the thickness of the slag layer varies in different positions. Usually located at the very deep part of the outlet, a wider and thinner surface and a thinner and narrower surface. Currently, there is little research on interfacial tension, but it is one of the factors that must be considered in the development of slag protection. Increasing the viscosity is also beneficial to improving the surface tension, but it is not conducive to heat conduction, which can be solved by lowering the melting point of the continuous casting slag. The following introduces the influence of the melting point of continuous casting slag: 1. Melting temperature The melting temperature of the flux has a great influence on the slag film thickness and mold heat flow. The slag film at the bottom of the crystallizer is thicker than that at the top, but the thickness increases with the increase of the melting point. The melting temperature of the continuous casting slag directly affects the thermal resistance of the slab and the slag film. The higher the melting point, the better the heat resistance of the slag film. In addition, as the temperature of the protective slag increases, the thickness of the protective slag film decreases, and the melting temperature of the crystallizer is extremely high, which is related to the critical thickness and drawing speed of the billet. For a given critical billet thickness, the faster the drawing speed, the lower the melting temperature. 2. Melting rate Continuous casting slag not only controls the thickness of the slag layer, but also

2023

Precautions for adding continuous casting slag

In actual production, the performance of continuous casting flux is closely related to the flux addition operation. Production practice has proved that even if the correct flux is selected, incorrect use will also cause problems with the slab quality. When adding continuous casting flux to the mold, it must be evenly distributed on the steel surface in the mold. When faults such as steel liquid level fluctuation, deviation, and casting stop occur during casting, corresponding measures must be taken. The following are precautions for adding continuous casting flux: 1. The operating procedure for adding continuous casting flux (1) Prepare fluxing tools: The fluxing tools are as follows: Ladle rod: The ladle rod is mainly used to remove large slag rings in the mold. During bonding, it is also used to test the shell to confirm the operation of the shell. A metal oxygen combustion tube or a wooden strip can be used. For the eddy current level monitoring system, a wooden slag catcher must be used. For other level monitoring systems, an oxygen combustion tube can be used, which is both convenient and practical. Ladle: Used to hold slag when changing slag and removing slag in the mold. Pusher rake: A tool for adding continuous casting flux to the mold. For eddy current level monitoring systems, wooden and wooden inference rakes should also be used to avoid interfering with the signal. Ladle shovel: Used to hold slag when changing slag and removing slag in the crystallizer. (2) Precautions 1)

2023

The role of continuous casting slag protection

What is the function of continuous casting flux? During casting, powder or granular slag is continuously added to the surface of the mold steel. This slag is called protective slag. Continuous casting flux has the following functions: (1) Heat insulation, preventing heat loss; (2) Isolating air, preventing oxygen in the air from entering the molten steel for secondary oxidation, affecting the quality of the steel; (3) Absorbing and dissolving inclusions floating from the molten steel to the steel-slag interface to purify the molten steel; (4) There is a slag film between the crystallizer wall and the solidified shell, which plays a lubricating role, reducing the pulling resistance and preventing the solidified shell from sticking to the copper plate; (5) Filling the gap between the shell and the crystallizer to improve the heat transfer of the crystallizer. A good protective slag should fully exert the above five functions to improve the surface quality of the billet and ensure the smooth progress of continuous casting. What are the requirements for the melting mode of continuous casting flux? In order to complete the above five functions, the protective slag added to the crystallizer during continuous casting must have a specified melting method, that is, a three-layer structure of powder slag layer, sintered layer and liquid slag layer is formed on the surface of the steel. Low-melting-point (1100 ~ 1200℃) slag powder is added to the surface of high-temperature molten steel (about 1500℃) in the crystallizer to form a certain thickness of slag on the surface of the molten steel.

2023

What is continuous casting flux?

2023

How should continuous casting slag be maintained?

The temperature of the continuous casting slag should be maintained within a reasonable range; excessively high or low temperatures will adversely affect the protective performance of the slag. Contamination of the protective slag by external harmful substances should be avoided, as these substances may cause the slag to fail. Furthermore, a good environment should be provided for the continuous casting slag to prevent corrosion. In addition, the use of the continuous casting slag should be checked regularly. If any abnormalities are found, measures should be taken promptly to eliminate the risk. Used continuous casting slag should be disposed of safely to prevent environmental pollution. The main causes of continuous casting slag failure are as follows: First, due to excessively low or high temperatures, the protective slag may be damaged, leading to failure. Second, corrosive gases may adversely affect the protective slag, leading to failure. In addition, due to a lack of effective maintenance, the structure of the protective slag may change, leading to failure. Furthermore, due to prolonged use, the structure of the protective slag may be worn, leading to failure. Due to environmental contamination, the structure of the protective slag may be damaged, leading to failure. To ensure the normal use of continuous casting slag, we should...

2023

Get to know continuous casting flux in one minute

Continuous casting slag is a brick-like solid substance formed by heating molten iron to a certain temperature and continuously stirring it. Due to its unique physical structure, it has strong corrosion resistance, protecting steel from oxidation by air during smelting. First, continuous casting slag has good acid and alkali resistance. During smelting, it can withstand the corrosion of acidic and alkaline liquids, thus protecting the steel surface from corrosion. Second, continuous casting slag has good thermal stability. Due to its good high-temperature resistance, it can withstand the high-temperature environment during smelting, protecting the steel surface from the influence of high-temperature melting. In addition, continuous casting slag has good wear resistance. It has high hardness and can withstand external impact, preventing wear on the steel surface and protecting the integrity of the steel structure. Continuous casting slag has good low-temperature resistance, can withstand low-temperature environments, is not affected by low temperatures, and protects the steel surface from freezing and cracking. Continuous casting slag is an important metallurgical technology that improves the properties of casting slag, improves material performance, and thus meets the high requirements of production. The principle of continuous casting slag is to add a certain amount of protective agent to the mold to inhibit the reaction between the mold and the casting slag, thereby protecting the mold and the casting.

2023

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Luoyang Turner High Temperature Instrument Co., Ltd.

+86-400-880-7095
Sales (same as WeChat):18695992058
Contact:+86-379-69755886
Address: South Section of Shuangxiang Road, Luoxin Industrial Cluster, Luoyang City, Henan Province
Email:tnkinstrument@163.com

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