Special electrometallurgy.

Special electrometallurgy covers new processes of melting and refining of metals and alloys that have been developed in the 50's 60's 20. to meet the needs of modern technology (space, rocket, nuclear, chemical engineering, etc..) in structural materials with high mechanical properties, heat resistance, corrosion resistance, etc. Special electrometallurgy includes vacuum arc melting (vacuum arc furnace), electron beam melting, electroslagremelting and plasma arc melting. These methods remelted steels and alloys responsible purpose, refractory metals - tungsten, molybdenum, niobium and their alloys, highly reactive metals - titanium, vanadium, zirconium, and alloys based on them and others. Vacuum arc melting was proposed in 1905 by von Boltonom (Germany) on an industrial scale, this method first used for melting titanium W. Kroll (USA) in 1940. Electroslagremelting method developed in 1952-53 at the Institute of Electric them. EO Paton USSR. For steels and nickel-based alloys particularly responsible destination using various versions of the duplex process, the most important of which - a combination of vacuum induction melting and vacuum arc remelting. A special place Special electrometallurgyisbeautifulyards vacuum melting, in which the heat sources are the electric arc, electron beam, plasma. These furnaces used for high and refractory metals (W, Mo and others, and their alloys), a portion of the liquid metal in the water-cooled crucible with skull used for ingots and shaped castings.

Theprocessofcasting.

In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods.Casting processes have been known for thousands of years, and widely used for sculpture, especially in bronze, jewellery in precious metals, and weapons and tools. Traditional techniques include lost-wax casting, plaster mold casting and sand casting.The modern casting process is subdivided into two main categories: expendable and non-expendable casting. It is further broken down by the mold material, such as sand or metal, and pouring method, such as gravity, vacuum, or low pressure.

Equipment and materials for electroslag casting.

Equipment

The standard equipment used for the ESC process and the auxiliary are practically the same as for the ESR method.

for producing cast products of any shape the water-cooled casting moulds were created in such a way that to provide the successive casting formation by gradual filling these moulds with metal during the electrode remelting.

Obviously, the most complex-shaped castings are obtainable by making use of the moulds which are stationary with respect to the castings. Such moulds may be subdivided into two types, the first comprising the moulds in which the casting is made as a whole, while in the second the linking part of the future article is cast first and the parts to be linked, already made by the ESC or another method and inserted into relevant holes of the mould, are fused up to the said linking part.

Materials

To run the ESC process provision is to be made for consumable electrodes, flux or its components to prepare liquid slag; electric power to generate heat in slag pool; water to cool casting mould, in some cases dry air, inert or other gas suitable for blasting slag and metal pool; compressed air or working fluid to control the operation of pneumatic or hydraulic equipment.

rior to be used, the flux is prefused in a graphite crucible by a graphite electrode, due to which a proper refining of slag from moisture, silica, iron oxides, sulphur and lead is achieved.

Date: 2015-12-24; view: 890