What are graphite crucibles used for? Protection and preservation of graphite crucibles
時間：2022-09-14瀏覽次數：3007Graphite cruciblePeople who are not in this field believe that they will be very strange, but they should be familiar with its smelting products, such as gold and brass. Graphite crucible can also be called copper melting ladle, copper melting, etc. It refers to a kind of crucible made of graphite, clay, silica and wax stone. Graphite crucible is mainly used for smelting copper, brass, gold, silver, zinc, lead and other non-ferrous metals and their alloys.
Graphite crucible is made of natural flake graphite as the main raw material and plastic refractory clay or carbon as the binder. It is characterized by high temperature resistance, strong thermal conductivity, good corrosion resistance and long service life. In the process of high temperature use, the thermal expansion coefficient is small, and it has a certain anti deformation ability for quenching and heating. It has strong corrosion resistance to acid and alkali solution, good chemical stability, and does not participate in chemical reaction during smelting. The inner wall of the graphite crucible is smooth, and the molten metal is not easy to leak and adhere to the inner wall of the crucible. Therefore, the molten metal has good fluidity and castability, and is suitable for various casting molds. Due to the above excellent properties of graphite crucible, it is widely used for smelting alloy tool steel, smelting non-ferrous metals and their alloys.
Graphite crucibles are mainly used to melt metal materials, which are divided into natural graphite and artificial graphite.
1. Natural graphite
The main raw materials are natural flake graphite, and refractory materials such as clay are added. The crucible is clay bonded, and the former is superior in strength and thermal shock resistance. It is used for smelting non-ferrous metals such as steel, copper, copper alloy, etc. It has a variety of specifications and smelting capacity ranging from 250g to 500kg.
This type of crucible includes accessories such as skimming ladle, cover, adapter ring, crucible support and stirring rod.
2. Artificial graphite
The above natural graphite crucible usually contains about 50% clay minerals, while the impurities (ash content) of artificial graphite crucible is less than 1%, which is used for refining high-purity metals.) <20ppm) through special refining process. Artificial graphite crucibles are often used to melt a small amount of precious metals, high-purity metals, refractory metals and oxides. It can also be used as a crucible for gas analysis of steel.
Protection and preservation
The graphite crucible needs moisture-proof, and the graphite crucible is afraid of moisture, which greatly affects its quality. The wet crucible will cause the loss of molten metal due to bursting, bursting, falling off, falling from the bottom, and even industrial accidents. Therefore, the graphite crucible shall be protected from moisture during storage and use.
The warehouse where graphite crucibles are stored shall be dry and ventilated, with a temperature of 5 ℃～ 25 ℃ and a relative humidity of 50-60%. Do not store the crucible on the brick soil or cement ground to avoid moisture. The bulk graphite crucible should be placed on a wooden frame, 25-30cm above the ground. The whole package shall be packed in wooden cases, wicker baskets or straw bags. Sleepers shall be placed under the cargo pile and not less than 20cm from the ground. A layer of linoleum on the sleeper will help prevent moisture from entering. The stack needs to be inverted for a period of time, and the bottom layer needs to be poured on the top layer. Preferably, the top layer and the bottom layer should be reversed, and the stacking time interval should not be too long. Generally once every two months, but if the ground is not wet, it can be stacked once every three months. In other words, multiple coats need to be applied frequently in order to achieve moisture resistance.
