Smelting characteristics of superalloy with the mo

2022-10-15
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Forging technology: smelting characteristics of Superalloy

superalloy parts, because they work under conditions of high temperature, heavy load and gas scouring, should not only consider high-temperature instantaneous strength, durability, creep, fatigue and other properties, but also consider high-temperature oxidation. Therefore, the metallurgical quality of the raw materials of this kind of alloy is highly required. In order to obtain high-quality alloy, it is necessary to accurately control the alloy composition, reduce the content of gas, harmful impurities and non-metallic inclusions in the alloy, and improve the purity of the alloy. Using electric arc furnace and non vacuum induction furnace to smelt under normal pressure can meet these requirements. During electric arc furnace smelting, the metal is affected by furnace refractory, slag, furnace gas and intermediate pouring process. Under atmospheric conditions, the more active elements such as aluminum and titanium in the alloy are easy to be oxidized and burned, and the metallurgical quality is difficult to be guaranteed. Therefore, the double process of vacuum induction smelting plus electroslag furnace remelting or vacuum consumable furnace remelting is required for superalloys

the change of gas (hydrogen, oxygen, nitrogen) content in GH2132 alloy after vacuum consumable remelting of electrodes melted by electric arc furnace is shown in Table 5, and the change of low melting point impurities (lead, silver, tin, antimony, arsenic) content is shown in Table 6. It can be seen from table 5 that the hydrogen content and oxygen content can be greatly reduced by vacuum consumable remelting, but the removal of nitrogen is not obvious. It can be seen from table 6 that after consumable remelting, the removal effect of lead and silver is obvious, arsenic and antimony are also reduced, and the removal effect of tin is small. The research also shows that for GH2132 alloy, due to the reduction of lead content to (0.2 ~ 0.4) and other reasons, the plasticity of the alloy is significantly improved, and the medium temperature low plasticity zone of the instantaneous tensile properties of the alloy is eliminated, which greatly improves the quality of reliable equipment for the environmental experiments that the alloy can endure under the continuous environment of extremely high temperature and extremely low temperature

table 5 gas content of electrodes before and after vacuum consumable remelting process. Due to the pre day operation in the water-cooled crystallizer under high vacuum, there is no pollution to the molten steel. Under the high-temperature arc light, the alloy partially becomes liquid due to solid state, and then condenses into ingots. This is a good purification. The low melting point non-ferrous impurities and gases that are most taboo in some superalloys can be removed, and the non-metallic inclusions are reduced, And the crystalline structure has been improved, so that the hot workability of the alloy has been significantly improved. At present, vacuum consumable furnace remelting process has become one of the best smelting methods of superalloys. Some important parts and components of modern engines, such as turbine discs and turbine blades, are melted by vacuum duplex or triplet process under such a good market demand environment

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