Issue 77

M. Al Khazali et alii, Fracture and Structural Integrity, 77 (2026) 56-70; DOI: 10.3221/IGF-ESIS.77.05

R ESULTS

Results of corrosion he amount of corrosion on the specimens was meticulously measured and quantified to provide a clear understanding of the extent of damage sustained under various exposure conditions. Quantifying corrosion is critical for understanding its effect on fatigue performance. Quantifying corrosion damage is essential for evaluating its influence on fatigue performance. The mass loss due to corrosion was determined for each specimen before and after exposure. The findings, which include corrosion loss in grams and grams per square meter, are presented in the following sections and tables. This thorough quantification yields a clear indication of corrosion damage for each exposure condition. The uncorroded specimens exhibited a bright metallic surface (Fig. 5). With increasing corrosion exposure, the metallic luster gradually disappeared, and corrosion products formed on the specimen surface. Localized corrosion pits became more pronounced with increasing exposure time (3 days, 6 days, and 6 + 3 days), which act as stress concentrators and promote fatigue crack initiation. After completing the rust removal process, a visual inspection reveals a hierarchical distribution of corrosion pits, with varying degrees of damage in each area. This observation indicates that as the corrosion duration increases (3 (35°C), 6 (35°C) and 6 (35°C) +3 (50°C) days), the size of corrosion pits gradually grows. To investigate the evolutionary pattern of time-varying corrosion damage in S460NL, the remaining weight of specimens was measured at different corrosion durations. The measured data revealed a certain deviation between the weights of corroded specimens in 3 (35°C), 6 (35°C) and 6 (35°C) + 3 (50°C) days and those without corrosion. Therefore, this study introduces several parameters for analysis, namely the measured corrosion loss, standard deviation s and coefficient of variation c. According to the data presented in Tab. 3, the mass loss rate of the specimens increases with increasing corrosion exposure time.  Note: Specimen dimension - d = 4 mm. l = 24 mm. A = 302 mm 2 = 0.000302 m 2 . T

Time of exposition days (temperature)

Mean corrosion loss (g/m 2 )

Mean corrosion loss (g)

Corrosion loss (g/m 2 )

s (g/m2)

Before test (g)

After test (g)

Corrosion loss (g)

s (g)

c (-)

n

1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

2.116 2.263 2.267 2.283 2.248 2.063 2.086 2.236 2.248 2.176 2.270 2.261 2.267 2.237 2.330

2.092 2.239 2.238 2.248 2.218 2.030 2.039 2.186 2.209 2.139 2.189 2.182 2.200 2.182 2.254

0.024 0.024 0.029 0.035 0.030 0.033 0.047 0.050 0.039 0.037 0.081 0.079 0.067 0.055 0.076

79.577 79.577 96.156 116.050 99.472 109.419 155.839 165.786 129.313 122.682 268.574 261.943 222.154 182.365

3 (35°C)

0.028

0.00413

94.167

13.687

0.145

6 (35°C)

0.041

0.00634

136.608

21.012

0.154

6 (35°C) + 3 (50°C)

0.072

0.00958

237.406

31.776

0.134

251.995 Table 3. Test results of corrosion parameters under different corrosion times.

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