PSI - Issue 36

Victor Shapovalov et al. / Procedia Structural Integrity 36 (2022) 262–268 V. Shapovalov, I. Protokovilov, V. Porokhonko / Structural Integrity Procedia 00 (2021) 000 – 000

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Fig. 3. View of the welded joints.

It should be noted that the gas composition of the weld metal fully meets the requirements of the standard for the Ti-6Al-4V alloy, which are: O ≤ 0.2%, N ≤ 0.05%, H ≤ 0.015%. This indicates that the developed procedures provide reliable protection of the weld metal from atmospheric gases contamination during the ESW.

Table 2. Chemical compositions of the weld metal.

Content, wt. %

Component

Ti H Weld metal 90,07 5,32 3,55 0,54 0,11 0,022 0,14 0,009 0,0024 Al V Zr Fe Si O N

The macrostructure of the cross-section of the welded joint is shown in Fig. 4. Three different zones are clearly visible: 1) the base metal, 2) HAZ, where structural changes occurred under the influence of the thermal cycle of welding and 3) weld metal.

Fig. 4. Macrostructure of the welded joint (cross-section).

The weld metal is characterized by columnar grain structure with crystals elongated in the direction of heat removal. This structure is typical for cast metal and is formed under conditions of a relatively low cooling rate and high heat input used for the ESW process. The fusion zone is blurred with a smooth transition from polyhedral equiaxial grains of HAZ metal to columnar crystallites of the weld metal. In general, the macrostructure of the metal is dense, no pores, slag inclusions or other defects were found.