Electron Beam Welding, Heat Treatment and Hardening of Beta-Titanium

2022

MSF

An expansion of titanium to mass production industries, such as the automotive, is prevented by its high extraction and production costs (e.g. extraction of titanium from its ores is 15 times and 3 times higher than that of iron and aluminum, respectively). One possible way to reduce the cost of titanium is to use cheaper alloying elements instead of vanadium or niobium to stabilize the body-centered-cubic β-phase. Iron has been considered for the development of few low-cost titanium alloys, such as the Ti–2.8Al–5.1Mo–4.9Fe, Ti-1.5Al-6.3Mo-4.4Fe and Ti-3.6Fe-0.25O alloys, because of its stabilizing effect of the β-phase. Nevertheless, due to the high density of iron, high quantity of β-stabilizing elements and the formation of TiFe-based brittle intermetallic phases, welding joints of low-cost titanium alloys are prone to formation of cold cracks which is very important limiting factor for obtaining welded joints with a strength of at least 90% compared to the strength of base material. Electron Beam Welding with its higher welding speed and intensity used in the process has its advantages over other welding methods in achieving the higher temperature required for melting and joining titanium alloys and obtaining welds with better mechanical properties. In this work the influence of the electron beam welding thermal cycle on the structure and mechanical properties of low-cost titanium alloys Ti–2.8Al–5.1Mo–4.9Fe, Ti-1.5Al-6.3Mo-4.4Fe and Ti-3.6Fe-0.25O will be studied.

Section: Introductionmentioning

confidence: 99%

Effect of Electron Beam Welding on the Microstructure and Mechanical Properties of Low-Cost Titanium Alloys

2022

MSF

“…Pseudo-β titanium alloys are rather sensitive to the welding thermal cycle, so it is necessary to study the effect on the welded joints properties of this alloy of such techniques as preheating [17] and local heat treatment after electron-beam welding (EBW) in a vacuum chamber [18,19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Pre-Heating and Post-Weld Local Heat Treatment on the Microstructure and Mechanical Properties of Low-Cost β-Titanium Alloy Welding Joints, Obtained by EBW

2022

DDF

Titanium (Ti) is highly valued for its strength-to-weight ratio and corrosion resistance. However, after it is processed to a wrought, or shaped form, it is typically in excess of 40 times more expensive than the corresponding steel part and nearly 20 times more expensive than the aluminum part. The high production costs of titanium in comparison to other structural metals is the main limiting factor for the wide employment of titanium. Cost reduction can be addressed considering creative fabrication methods and/or formulating new chemical compositions. In general, low-cost technology of titanium alloy can be implemented from raw material, alloy design and processing and forming. The core idea of low-cost titanium alloy design is to use cheap alloying elements to instead of expensive alloying elements without reducing the performance of the alloy. Iron has been considered for the development of few low-cost titanium alloys because of its stabilizing effect of the β-phase. Besides, it has a large solid solubility in β-Ti and owing to the atomic size difference with Ti can enable significant solution strengthening. But due to the high density of iron, high quantity of β-stabilizing elements and the formation of TiFe-based brittle intermetallic phases, welding joints of low-cost titanium alloys are prone to formation of cold cracks which is very important limiting factor for obtaining high quality welded joints with a strength of at least 90% compared to the strength of base material. Electron Beam Welding with its higher welding speed and intensity, can prevent formation of intermetallic and could help in obtaining welds with better mechanical properties, especially in combination with either pre-or post-welding heat treatment. The aim of this work is to study the effect of pre-heating and post-welding heat treatment on low-cost β-titanium alloy Ti-2.8Al-5.1Mo-4.9Fe welding joints by performing electron beam welding in combination with pre-and post-welding heat treatment. Specifically, this work will help to understand the influence of such techniques on the structure, phase composition and mechanical properties of low-cost β-titanium alloy welded joint.

“…Intensive work is underway in leading material science centers in the USA, EU, Russia, and China, both to modernize existing titanium alloys and to create new ones [1][2][3][4][5][6][7]. Extensive research is also underway to study the weldability of titanium alloys [8][9][10][11][12][13][14][15] and their practical application in various fields [16][17][18][19][20][21][22][23][24][25]. The E.O.…”

Section: Introductionmentioning

confidence: 99%

Structure and Properties of High-Strength Titanium Alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr Welded Joints

et al. 2021

SSP

As intensive work is underway in leading material science centers in the USA, EU, Russia, and China, both to modernize existing titanium alloys and to create new ones, the E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine developed titanium alloys T110 (Ti-5.5Al-1.2Mo-1.2V-4Nb-2Fe-0.5Zr system) and T120 (Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr system), which according to their characteristics, belong to the group of modern two-phase high-alloyed alloys characterized by high strength and good ductility. With more and more attention is being paid to the expansion in the usage of welded structures and assemblies of high strength titanium alloys with UTS ≥ 1100 MPa, there’s urgent need in studying best ways to obtain welded joints from such alloys. The weldability of two-phase high-alloyed titanium alloys, the use of which can give big reduction in structural weight, is significantly worse than low-alloyed alloys, therefore for a new alloy it is necessary to ensure the possibility of obtaining welded joints with a strength of at least 90% compared to the strength of base material. The aim of this work is to study the influence of the welding thermal cycle and reducing of weld metal alloying degree on the structure and mechanical properties of welded joints of high-strength titanium alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr with tensile strength more than 1200 MPa, as well as assessment of it welded joints properties in comparison with other high-strength titanium alloys.