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Home Material Sciences Chamber Electroslag Remelting (Chesr) – A New Method For Enhanced Quality Ingot Production From Titanium And Titanium Alloys

Chamber Electroslag Remelting (Chesr) – A New Method For Enhanced Quality Ingot Production From Titanium And Titanium Alloys

Description

Today, full-scale implementation of titanium and its alloys is restricted by its high price, which determined by complex and multi-stage technology of production. Vacuum-arc remelting, electron-beam and plasma-arc cold hearth melting are the main technological processes for producing of titanium and its alloys ingots. But in some cases these processes can not to provide the necessary quality of metal. ESR is an outstanding alternative to vacuum processes; characterized by relatively simple equipment, flexibility of technological parameters, high quality, and low production cost. But “classic” ESR, which is open to the atmosphere, does not permit production of ingots from highly reactive metals, such as titanium, chromium, vanadium and other. The Donetsk National Technical University (earlier known as Donetsk Polytechnic Institute) has a long history of scientific research, development and investigation of ESR technology. In recent years, research has focused on a new variant of the technology – ESR in controlled atmosphere under “active” metal-containing fluxes (ChESR). As was shown in the series of the research works, fulfilled in DonNTU, the electroslag remelting of metals and alloys under slag systems with active additions in the chamber type furnaces permits to solve the problems, for which application of traditional methods of electrometallurgy causes the difficulties or in some cases, is impossible. Producing of high-quality ingots of titanium, its alloys and intermetallides may be considered as problem of this type.

Innovative Aspect and Main Advantages

Presence of chamber and controlled atmosphere creates the favorable conditions for effective refining, modification, and alloying of metals and alloys due to using of active components of slag (calcium, rare-earth elements and other) during the remelting process. In current time, the theoretical basis of this process and technologies for manufacturing of high-quality ingots from various reactive metals such as titanium, chromium and their alloys are developed by DonNTU scientists.

  • High quality after the first remelting (good chemical and structure uniformity and perfect lateral surface of ingot, which does not demand the machining);
  • Possibility to guarantee the decreasing content of impurities (for example, nitrogen-rich inclusions);
  • Decreasing of number of remelting steps for obtaining of quality ingots;
  • Possibility of obtaining of square and rectangular crosssection of ingots, that is very important for following treatment by pressure;
  • Using of simple and inexpensive equipment;
  • Decreased energy consumption.

Areas of Application

This technology may be used for solving of various tasks:

1. Producing of high-quality titanium ingots from titanium sponge or powder. This task may be divided on two separate ones:
a) The producing of cast compacted ingots from titanium sponge or titanium powder with quality close to quality of iodide titanium. Content of impurities in titanium ingots after ChESR is at following level: 0.03% O; 0.005% N; 0.003% H; 0.01% C (weight percent). The hardness of metal is less then 100 HB. The ingots 100 - 200 mm in diameter may be the commercial product and may be used for application of coatings in electronic industry, as a getter in superhigh-vacuum pumps, in the medicine (stomatology in particular), for superconductive and magnetic alloys. Main advantage of titanium, produced by ChESR, is the lower price in comparison with iodide titanium (5 - 6 times lower in conditions of Ukraine).
b) Producing of ingots of titanium and its alloys by ChESR as alternative to vacuum arc remelting, electron-beam and plasma-arc cold hearth melting.

2. Refining of TiAl master alloy, obtained by the method of aluminothermic reduction of titanium oxides, in process of compact ingot manufacturing.

3.Recycling of titanium wastes (scrap, chips), Chamber ESR may be perspective method for producing of ingots of other metals with high reactive activity. - Zr, V, Cr, and their alloys.


Fig. 1 Titanium ingots, produced by ChESR

Stage of Development

Technology has been successfully tested in the laboratory and pilot plant conditions for producing of ingots up to 200 mm in diameter and may be proposed as the basis for commercial technology development.

Contact Details

Dr., Prof. Anatoliy D. Ryabtsev, Head of Laboratory of Electrometallurgy
Donetsk National Technical University
Artyoma, 58 Donetsk 83000, Ukraine
Phone: +38062 305-3262
Fax: +38062 305-3262
E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

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