PSI - Issue 81

Anatolii Klymenko et al. / Procedia Structural Integrity 81 (2026) 470–477

473

The corrosion behavior of Inconel 601 alloy in molten lead for test durations of 240, 720, 1000 and 1440 hours was characterized by a decrease in the corrosion rate by eight times at a temperature of 450 °C, and by two times at 650 °C, which is due to partial blocking of the alloy surface by oxide films and corrosion products. However, increasing the melt temperature from 450 °C to 650 °C led to an increase in the corrosion rate of the alloy by fifteen times at the beginning of the studies, to more than a hundred times after 1440 hours. The results of measuring the corrosion rate of the alloy are given in Table 1.

Table 1. Corrosion rate of the studied alloy Inconel 601 Temperature, °C Corrosion rate, mm/year

Test duration, h

0.115/1.680 0.110/1.600 0.075/1.280 0.025/1.280 0.010/1.155

240 480 720

450/650

1000 1440

Local chemical analysis of corrosion products

Corrosion damage of samples of Inconel 601 alloy in molten lead is associated with the formation of intermetallic compounds of lead with nickel, as well as the oxidation of other chemical elements of the alloy by oxygen dissolved in the melt. At a temperature of 450 °C, the oxidation process is dominant in comparison with the process of formation of intermetallics, which causes uniform damage to the alloy surface, which is also reflected in the formation of an almost uniform layer of corrosion products on the alloy surface. Increasing the temperature to 650 °C leads to an acceleration of the formation of intermetallic compounds of lead with nickel, which becomes dominant in comparison with the oxidation process, which leads to the etching of both individual grains of the alloy and entire "conglomerates" of grains, with their separation from the alloy matrix and diffusion into the lead melt volume. At the same time, the lead melt diffuses into the formed voids of the near-surface layer of the alloy. The combination of these processes contributed to the formation of a layer of corrosion products on the surface of the alloy that is heterogeneous in both composition and thickness. Table 2 presents the results of measuring the thickness of the layer of corrosion products in molten lead depending on its temperature and exposure time.

Table 2. Thickness of corrosion products studied alloy Inconel 601 Temperature, °C Corrosion products layer thickness, min.-max. values (average), µm Test duration, h

54 (54)

240 720

450

3-30 (16.5) 10-246 (93) 47-109 (85.3)

1440

240 720

650

339 (339)

348-364 (356)

1440

According to the results of the study, it was found that with an increase in temperature from 450 °C to 650 °C, the thickness of the corrosion product layer (average values) increases from 54 to 85 μm after 240 h of testing. With an increase in the durat ion of testing from 240 to 1440 h, the thickness of the layer of formed corrosion products increases from 54 to 93 μm and from 85 to 356 μm, respectively, at 450 °C and 650 °C (see Table 2). The results of scanning microscopy on the nature of changes in the structure and composition of the corrosion product layers formed on the surface of the Inconel 601 alloy, depending on the duration of testing at 450 °C and 650 °C, are presented in Fig. 3 and Fig. 4, respectively.

Fig. 3. Microsection of Inconel 601 alloy with the measurement results after exposure in lead melt for 240 h (a), 720 h (b) and 1440 h (c) at 450°C.