The Paton Welding Journal, 2023, №04



2023 №04 (03)

DOI of Article 10.37434/tpwj2023.04.04

2023 №04 (05)

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The Paton Welding Journal, 2023, #4, 28-34 pages

Structure and properties of ingots produced from sheet cuttings of VT-1 titanium by electroslag remelting in an open mould

D.I. Bilonyk¹, O.Ye. Kapustyan¹, I.A. Ovchynnykova², I.M. Bilonyk¹, G.M. Lapteva¹

¹National University «Zaporizka politekhnika». 64 Zhukovskogo Str., 69063, Zaporizhzhya, Ukraine. E-mail: aek@zntu.edu.ua
²Zaporizhzhya National University. 66 Zhukovskogo Str., 69600, Zaporizhzhya, Ukraine.

Abstract
Analysis of technologies, allowing titanium wastes to be used in the melting process in ingot production, was performed. It is shown that for this purpose a promising and cost-effective schematic is the one which includes electroslag remelting with preliminary manufacture of a consumable electrode completely from standard wastes of sheet cuttings of VT1-0 titanium. The structure and properties of electroslag ingots of titanium of 90×90 mm cross-section and 85 mm diameter was studied. The ingots were produced with application of electroslag remelting in an open mould with sliding current conduit and the slag pool surface protection by argon. Chemical composition of electroslag ingots of unalloyed titanium practically does not differ from that of titanium of VT1-2, VT1-L grades, and a whole range of grades of unalloyed titanium from foreign manufacturers, except for a somewhat higher content of oxygen and nitrogen. Ultrasonic testing of the ingots did not reveal any internal defects. Macrostructure, which was studied on longitudinal and transverse templates, is coarse-crystalline, dense, and homogeneous without any defects of technological origin. The angle of inclination of the columnar crystallites to the ingot axis is 40…45°, grain size is 1.8…2.5 mm. The microstructure consists of transformed β-grains of 140…175 μm size. After annealing (620 °С) the mechanical properties of electroslag ingots were as follows: НВ = 224; σt = 590 MPa; σ0.2 = 560 MPa; δ = 7.5 %; ψ = 13.5 %. Technical measures were determined to improve the ductility of electroslag titanium by reducing the content of oxygen and nitrogen in the ingots, and refining the cast grain size. Technological properties of electroslag titanium (cuttability and weldability) are on the level of VT1-L. The possibility of pressure treatment (hot forging) was established with deformation coefficients of 40 and 90 % of titanium from electroslag ingots. The obtained semi-finished products did not have any internal or surface defects. Ref. 24, Tabl. 2, Fig. 8.
Keywords: processing; sheet cuttings; titanium; electron beam meting; electroslag process; ingot; structure; chemical composition; mechanical properties; technological properties; hot forging


Received: 26.12.2022
Accepted: 25.05.2023

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