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Electron beam melting of titanium

SE «SPC «Titan» of the E.O. Paton Electric Welding Institute of the NAS of Ukraine® developed and introduced into industrial production the technology of electron beam melting of ingots of unalloyed titanium of grades VT1-00, VT1-0, Gradel, Grade2, which is characterized by:

• ability to use as initial charge material both titanium sponge and lump wastes of titanium production, as well as prepared chips, and here the amount of wastes used in the charge can reach 100 %;
• elimination of expensive operation of consumable electrode compacting from the process cycle;
• guaranteed removal of refractory nonmetallic inclusions of both high and low density;
• production of structurally and chemically homogeneous titanium ingots of both round and rectangular cross-section from initial charge in one remelting cycle.

The following can be used as initial charge: titanium sponge of different fractions, pelletized titanium sponge, as well as titanium scrap and prepared chips.

Electron beam melting of commercial titanium alloys

Fundamental studies conducted at the E.O. Paton Electric Welding Institute of the NAS of Ukraine of the processes of alloy component evaporation from the melt in vacuum and ingot solidification at EBM allow
prediction of chemical composition and structure of produced ingots of titanium alloys, and enable producing ingots of guaranteed composition. Application of cold hearth allows avoiding penetration of refractory inclusions of high and low density into the produced ingots. SE «SPC «Ti- tan» of the E.O. Paton Electric Welding Institute of the NAS of Ukraine® mastered the technology of producing ingots of titanium alloys for structural applications (3M, VT5, PT- 7M, PT-ZV, VT6, VT14, VT20, VT22, VT23, T110, etc.) and of high-temperature titanium-based alloys (VT5-1, VT3-1, VT8, VT9, VT25U, etc.).
Technology of electron beam melting allows producing titanium-based alloys with not more than 0.002 % hydrogen content and equiaxed fine grain, both in transverse and in longitudinal section of the ingot that increases technological ductility of metal during subsequent thermomechanical treatment and improves the uniformity of mechanical properties of produced semi-finished products.

Production of new titanium-based alloys

В ГП «НПЦ «Титан» ИЭС им. Е. О. Патона НАН Украины» освоена технология выплавки разработанного в ИЭС им. Е. О. Патона НАН Украины нового высокопрочного титанового сплава Т110 (Тi—5Аl—1Мо-1V—4NЬ-2Fe-0,5Zr). Особенности титанового сплава Т110 — высокая удельная прочность, по которой он не уступает высокопрочному сплаву ВТ22, а также повышенная устойчивость к образованию усталостных трещин и технологическая пластичность, что позволяет применять его в качестве материала защитного назначения в авиастроении. По ряду служебных характеристик, например, по усталостной долговечности, сплав Т110 превышает показатели сплава ВТ22 на 15-20 %.

Mechanical properties of high-strength titanium alloys

Alloy	σ0,2, MPa	σa, MPa	δ, %
Ti-6Al-4V	795	860	10
Ti—10V-2Fe-3Al	1100	1170	6
BT22	990	1080	8
T110	1060	1100	15

SE «SPC «Titan» of the E.O. Paton Electric Welding Institute of the NAS of Ukraine® gained extensive experience of producing ingots based on titanium aluminides (Ti₃AI, TiAl intermetallic compounds), which have high heat resistance, thermal stability and low specific weight, making them promising materials for application in aircraft engines and other aerospace engineering products. Developed EBM technology allows producing titanium aluminide ingots with additional alloying by refractory and rare-earth elements.

Mechanical properties of an alloy based on titanium aluminide produced by EBM

Ti-44AI-5Nb-2Cr-1,5Zr-1B	Compressive yield strength σ0,2		Compressive ultimate strength σ0,2, MPa		Bending strength σt, MPa	Modulus of elasticity E, GPa
Testing temperature, °C	20	900	20	900	20	20
Cast alloy	1078	640	1660	1050	583	155

Electron beam glazing of ingot surface

Machining is traditionally performed for ingots at different stages of metal processing. Amount of wastes is usually equal to 5-15 % of treated ingot weight. To reduce metal losses, the E.O. Paton Electric Welding Institute of the NAS of Ukraine developed and introduced into production a technology of glazing by electron beams the side surface of ingots of both round and rectangular cross-section, instead of machining, and designed the respective equipment for its realization.
Technology of electron beam glazing of side surface of ingots allows removing surface defects without machining the ingot surface that increases metal yield up to 15 %, depending on ingot weight.

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