News

　　 Melting furnace It refers to equipment used to melt metal ingots and some scrap metal, add the necessary alloying elements, and then refine the molten material through processes such as slag removal and refining, ultimately producing the desired alloy.

　　I. Melting Furnaces Classified by Heating Energy Source

　　Melting furnaces can be classified into two categories based on their heating energy:

　　1. Heating fuels (including natural gas, liquefied petroleum gas, coal gas, diesel, heavy oil, coke, etc.) heat the charge material by utilizing the reaction heat generated during fuel combustion.

　　2. Electric heating type: The resistive element heats up when current flows through it, or an alternating current flowing through a coil generates an alternating magnetic field, which in turn induces a current that heats the charged particles within the magnetic field.

　　II. Melting furnace Classified by heating treatment method

　　1. Direct heating method

　　The heating method in which the heat generated by fuel combustion or by resistive elements is directly transferred to the furnace materials is called direct heating. Its advantages include high thermal efficiency and a simple furnace structure. However, its disadvantages include the adverse effects of harmful impurities contained in combustion products on the quality of furnace materials: harmful gases emitted from furnace materials or covering agents can corrode refractory elements, thereby shortening their service life; during fuel combustion, if the air content in the combustion products is too high, it leads to significant metal burn-off during the heating process.

　　2. Indirect heating mode

　　There are two types of indirect heating methods. The first involves using combustion products or resistive elements that do not directly heat the charge itself; instead, they first heat a heat-transfer medium, such as a radiant tube, and then transfer heat to the charge via radiation and convection. The second method uses an alternating magnetic field generated by an AC current flowing through a coil, which heats the charge via induced currents. The beneficial effects of this invention are that the combustion products or electric heating elements are separated from the charge, thus avoiding any harmful interactions between them. Induction heating also has a stirring effect on the molten metal, which can accelerate the melting process, shorten the melting time, and reduce metal burn-off losses. However, its drawback is that heat cannot be directly transferred to the charge; compared with direct heating methods, it has lower thermal efficiency and a more complex furnace structure.

　　Three, Melting furnace Classified by operating mode

　　1. Continuous melting furnace

　　In a continuous furnace, the charge is loaded from the charging side. Inside the furnace, following a predetermined temperature profile, various processes such as heating and holding at specific temperatures can be carried out sequentially. The material then exits continuously from the discharging side at a steady rate or according to a specified working cycle and interval. Continuous furnaces are particularly suitable for enterprises that produce a limited variety of products in large batches.

　　2. Batch Melting Furnace

　　In a batch furnace, charge materials are added to the furnace in batches according to a specific economic cycle. Following a predetermined temperature profile, the furnace can complete various processes such as heating and holding at different temperatures before the entire batch is discharged from the furnace. Batch furnaces are particularly suitable for enterprises that produce a wide variety of products with numerous specifications.

　　4. Melting furnaces are classified according to the atmosphere inside the furnace.

　　1. Unprotected gas-type melting furnace

　　The furnace atmosphere is either air or the combustion atmosphere of the fuel itself. This atmosphere is primarily used to form a dense protective layer on the surface of the furnace charge at high temperatures, thereby preventing severe oxidation of the product under high-temperature conditions.

　　2. Protective gas type Melting furnace

　　If the oxidation level of the charge material is difficult to control, the furnace is typically evacuated to a low vacuum and then filled with protective gases such as nitrogen or hydrogen to prevent the charge material from undergoing vigorous oxidation at high temperatures. As the requirements for both internal and external product quality continue to rise, the application scope of protective-gas furnaces is steadily expanding.