PSI - Issue 59

Anatolii Klymenko et al. / Procedia Structural Integrity 59 (2024) 214–221 Anatolii Klymenko et al. / Structural Integrity Procedia 00 (2019) 000 – 000

220

7

Element, Weight %

O

Si

Ti

Cr

Mn 0.76

Fe

Ni

Mo

Pb

S1 S2 S4 S5 S7 S8

25.45 0.40 10.93 1.70 25.65 0.39

- - -

10.23 0.61

37.69 1.93 36.42 20.33

6.62

- - - - - -

18.85 84.83 19.59 40.94 76.85 30.76

-

9.34 6.55 1.06

0.59

8.02 3.56 0.55 4.06

26.32 15.77

- -

2.31

-

-

5.78

25.08 0.52

0.32 0.35

10.03 12.97

0.78 0.77

28.44

S9 (BM)

-

0.51

58.02 24.97 2.40

-

Element, Weight %

O

Si

Ti

Cr

Mn

Fe

Ni

Mo

Pb

S1 (BM)

-

1.08 1.17 18.75 1.71 66.23 9.64 1.43

-

S2 S3 S4 S5 S6

66.60 69.71

- -

- - - - -

2.38 2.49 8.96 1.61 8.31

- -

7.64 6.94

1.32 0.92

- - - - -

22.06 19.95 5.60 33.92 5.72

52.62 0.66

0.87 29.51 1.78

59.03

-

-

2.41

3.03

58.37 0.72

0.88 25.04 0.96

Element, Weight %

O

Si

Ti

Cr

Mn

Fe

Ni

Mo

Pb

S1 (BM) 0.36 0.48 8.97 15.00 1.73 58.64 10.23 -

- - -

S2 (BM) 6.40

-

67.20 1.53

-

4.09

0.53 9.08 1.11 2.67

-

S3 (BM) 0.64 0.55 0.41 17.88 1.75 67.32

2.37

S4 S5

24.69 0.43

- -

12.06 1.30 32.28

- -

28.14 77.46

12.71

-

1.15

-

6.01

Impurities «N» (20.25 S2 BM); «S» (4.58 S1 BM)

Fig. 6. The micro-x- ray spectral analysis results after exposure of AISI 316L steel in lead melt for 240 (а), 720 (b) and 1440 h (c) at 650 °C.

An increase at 650 °C already after 240 h of testing (Fig. 6a) leads to the formation of corrosion products in the form of a multilayer structure with clear separation and successive alternation of layers based on lead (from 19.59 to 84.83 wt.%) and based on lead (from 18.85 to 30.76 wt.%) and iron (from 28.44 to 37.69 wt.%), significantly prevailing in thickness. The oxygen concentration increases when moving from a layer based on lead (~ 13 wt.%) to a layer based on lead and iron (~ 25 wt.%). However, after 720 h (Fig. 6b), a conglomeration of multilayer formations is already observed with an increase in the thickness of layers based on lead boundary on the steel surface (22.06 wt.%) and porous upper (33.92 wt.%) corrosion products, and also medium uneven structures based on lead and iron with cohesive cracking and local chaotic intrusions of formations based on lead (in layers based on iron and lead) and iron lead (in layers based on lead). In addition, the oxygen concentration significantly increases (up to ~ 70 wt.%) in the corrosion products layer. After 1440 h (Fig. 6c), the formation of almost complete adhesive cracking of the corrosion products layer is observed. The corrosion of stainless steel AISI 316L in a lead melt is characterized by the penetration of lead from the melt into the depth of the matrix already after 240 h of testing due to damage to the surface layers, as well as the formation of a layered structure of oxidation products with a change in the concentration of the component composition of the layers with time. On the one hand, this is due to the uneven changes in the concentration of lead both in the surface layers of corrosion products and in oxide films formed directly on the steel surface (see Fig. 5-6). On the other hand, a violation of the integrity of the oxide layer of both lead itself and other metals and their concentrations that are part of the corrosion products is imposed. Predominantly, as they form of the oxidation products surface layers differ from the base metal composition by the presence of Pb and the absence of Mo and Ti. As the test temperature increases from 450 to 650 °C, the oxygen concentration increases from 10.56 wt.% to ~70 wt.%. However, the distribution of