PSI - Issue 40

E.E. Abashkin et al. / Procedia Structural Integrity 40 (2022) 1–6 Abashkin E.E. / Structural Integrity Procedia 00 (2022) 000 – 000

3

3

The welding process was performed by mince of ADF-1000 welding unit for automatic SAW by feeding electrode wire into the local heating zone. The experimental electrode designed as a flux-cored wire is shown in Figure 1. A flux-cored wire with 0.42% filling ratio was used during this experiment. The following ratio (mass. %) of components was utilized: iron scale (Fe3O4) 71.9%; aluminum powder (Al) 23.86%; ferrosilicon FS50 (GOST 1415-93) 1.77%; ferromanganese FMn78 (GOST 4755-91) 2.14%; graphite electrodes powder EG15 (TU 14-139 177-2003) 0.33%. The components with fractions range 0.1 - 0.2 mm were used for aluminothermic filler composition. The diameter of the final e lectrode equals Ø = 2.8 mm (Abashkin et al., 2017).

Fig. 1. Shape and reference sizes of aluminothermic filler components: (a) flux-core wire cut front view; (b) components of aluminothermic filler.

St3sp steel joint was fabricated with a one-time (single pass of the electrode) combined thermal exposure on the contact zone of the parent metal. The temperature effect in the contact zone of the connected structural elements is regulated by the current I (A), which leads to an increase in thermal power of the arc. Table 1 shows the modes of metal formation.

Table 1. Mode characteristics of deposited metal formation. Mode I i , A U i , B

V i , м/ч

qi, kJ/sec.

1 2 3 4

200 250 300 350

35 35 35 35

20 20 20 20

7.6 8.1 9.5

11.1

3. Results Impact bending tests were conducted as per GOST 9454- 78 “Metals. Method for testing the impact strength at low, room and high temperature”. The shape and dimensions of test samples corresponded to a U-type concentrator with a radius of R = 1 ± 0.07 mm, regulated by GOST 9454 -78. The value of the impact strength was determined by a pendulum impact tester MK type, as per GOST 10708-82. The test results (figure 2) have shown that an increase in the thermal power of the arc up to 9.5 kJ/s leads to an increase in the impact strength of the weld material in the permanent joint and reaches a value of 66.7 kJ/m2 at mode 3. The subsequent increase in the thermal power of the arc is more than 9.5 kJ/s leads to a decrease in the value of impact strength. When determining the physical-mechanical properties of a weld in the permanent welded structure, the tests were carried out as per GOST 6996 - 66, and specimens were fabricated subjected to the requirements of GOST 1497-84