Page 31 - May

METALWORKING EQUIPMENT AND TOOLS

In addition, when welding suspended, which is typical for welded products and structures
for which it is impossible to use bulky forming shims, poor formation of the weld penetration is
observed with a large penetration sagging and a sharp transition from the penetrated metal to
the base metal. This leads to a decrease in performance, especially under dynamic loads.
An effective way to combat the above disadvantages is the proposed method of TIG welding
(argon arc welding with a non-consumable electrode), which consists in using flux tape for
welding [2]. The flux tape is attached to the surface of the edges to be welded on the back
of the weld and can be carried out in several options depending on the thickness of the metal
being welded, the spatial position of the joint, the configuration of the welded joint, etc. The use
of a flux-cored tape, firstly, prevents sagging of the weld penetration, and secondly, contributes
to a significant reduction in the number of defects in the welded seam and, thirdly, protects the
molten metal of the weld pool from the influence of the surrounding atmosphere.
The aluminum-magnesium AMg6 alloy, widespread at shipbuilding enterprises in Eastern
Europe, was used as aluminum alloys for research, the composition of which is shown in Table
1. Preparation of welded plates for TIG welding according to standard technology was carried
out with Y-shaped groove (Figure 1a), and with the use of flux tape - without cutting the welded
edges (Figure 1b).

flux tape
a b

Fig. 1. Schemes for preparing the edges of the welded plates: a - for welding using standard technology, b - for welding
using flux tape.

A flux tape was obtained by applying a flux with a width of 10 mm and a thickness of 0.2
- 0.4 mm on the surface of a flexible and thin fiberglass tape, which was attached to the plates
to be welded from the side of the penetration. As a flux, applied in the form of a paste to the
tape, we used a TFA-12 flux [3]. TIG welding modes of AMg6 aluminum alloy using conventional
technology without flux tape in two passes and with the use of flux tape in one pass are given
in Tables 2 and 3. Clogging of welded seams with oxide inclusions was estimated by the value
of the relative length of oxide inclusions (Δo.w), which was determined the ratio of the sum of
oxide inclusions in the weld (Σlo.w) to the total length of the weld (lшва):

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