uhp graphite electrode for eaf smelting
The graphite electrode ceramic made by uhp graphite electrode for eaf smelting
We may not understand what uhp graphite electrode for eaf smelting is. Let’s introduce to you. We can also use graphite electrode to make graphite electrode ceramics. Let us also look at the preparation of graphite electrode ceramics. Uhp graphite electrode for eaf smelting is a man-made material with a molecular formula of SiC, and graphite electrode occasionally exists on meteorites and the crust. The graphite electrode has a molecular weight of 40.07 and a density of 3.16～3.2g/cm3. SiC has two crystal forms: α and β. When the temperature is lower than 1600°C, SiC exists in the form of β-SiC, and when the temperature is higher than 1600°C, β-SiC transforms into the form of α-SiC. Uhp graphite electrode for eaf smelting is dominated by covalent bonds, and covalent bonds account for about 88%.
The basic structure of the lattice is SiC4 and CSi4 tetrahedrons interspersed with each other. Due to the different stacking order of tetrahedrons, different structures are formed. So far, hundreds of variants have been found, such as 3C-SiC, 4H-SiC, 6H-SiC and so on. The chemical stability of the graphite electrode is closely related to its oxidation characteristics. The graphite electrode itself is easy to oxidize, but after it is oxidized, a silicon dioxide film is formed, and the oxidation process is gradually hindered. In the air, the graphite electrode starts to oxidize at 800°C, but very slowly; as the temperature increases, the oxidation speed increases rapidly.
The oxidation rate of uhp graphite electrode for eaf smelting is 1.6 times faster in oxygen than in air; the rate of oxidation slows down over time. Pure graphite electrode is a colorless and transparent crystal. Industrial graphite electrodes are colorless, light yellow, light green, dark green, light blue, dark blue and black. The degree of transparency decreases with increasing color. The abrasive industry divides the uhp graphite electrode for eaf smelting into two types, black graphite electrode and green graphite electrode, according to their color. Among them, colorless to dark green are classified into the green graphite electrode category, and light blue to black are classified into the black uhp graphite electrode for eaf smelting category. The mechanical properties of the black and green graphite electrodes are slightly different. The green graphite electrode is more brittle, and the made abrasive tools are rich in self-sharpening; the black uhp graphite electrode for eaf smelting is tougher, so the two graphite electrodes have different uses. different.
Preparation of uhp graphite electrode for eaf smelting ceramic made of graphite electrode 1 Preparation of ultra-fine graphite electrode powder In recent years, the preparation methods of ultra-fine graphite electrode powder developed in the high-tech field are mainly classified into three types:
Solid phase method, liquid phase method and gas phase method.
a The solid phase method mainly includes the following: carbothermic reduction method, direct reaction method of Si and C (including high-temperature self-propagating synthesis method and mechanical alloying method).
b The liquid phase method mainly includes the following: sol-gel method, polymer thermal decomposition method and solvothermal method. c The gas phase method mainly includes the following types: gas phase reactive deposition (CVD), plasma method, and laser induced gas phase method. 2graphite electrode ceramic preparation uhp graphite electrode for eaf smelting is a typical covalently bonded stable compound. With its low diffusion coefficient, it is difficult to achieve densification by conventional sintering methods, and some sintering aids must be added To reduce the surface energy or increase the external pressure to achieve sintering.
Reaction sintering graphite electrode ceramics is a method of using α-SiC and C as raw materials, adding an appropriate amount of binder for molding and drying, and then placing it in a buried material containing Si. When the green body is heated in the furnace over 1400°C, the Si around the green body melts, or penetrates into the capillary of the green body in liquid or gaseous state, and reacts with C in the green body to form SiC. The generated SiC gradually fills the pores in the green body, and connects the original α-SiC, and finally achieves the densification of the product and gains strength.
Hot-press sintering graphite electrode ceramic hot-press sintering is to apply a certain pressure during the sintering process. The existence of pressure increases the atomic diffusion rate and the sintering driving force, thereby speeding up the sintering process. However, under high pressure conditions, crystal grains oriented perpendicular to the pressure direction will appear in the sintered body. In order to avoid this phenomenon, a hot isostatic pressing sintering method can be used. c. Pressureless sintering uhp graphite electrode for eaf smelting Ceramic pressureless sintering is considered to be the most promising sintering method for SiC sintering. Through the pressureless sintering process, SiC parts with complex shapes and large sizes can be prepared.
According to the different sintering mechanism, pressureless sintering can be divided into solid phase sintering and liquid phase sintering. When the carbon company was founded, it established the development strategy of “science and technology, innovation, and leadership”, adhering to the business philosophy of “quality first, service first”, through technological improvement, quality improvement, and market development, carbon has become a region in Shanxi, Hebei, and Mongolia. The largest graphitization processing company. The main business includes graphite electrode, Shijiazhuang uhp graphite electrode for eaf smelting, graphite electrode. Tel: