*3.1. Uniform Corrosion*

After 12 days, the salt fog test revealed that here was a difference in the corrosion susceptibility of transverse and longitudinal surfaces (Figure 5). In general, the transversal surfaces were corroded, with the exception of steel #3, the intensity depending on the steel grade and the manufacturing process. Samples #3, #4 and #5 were made of grade 316L, from three different steelmakers (Germany, France, Italy). The longitudinal surfaces showed no signs of corrosion.

**Figure 5.** Uniform corrosion salt fog test, according to ASTM B 117-97. Samples #2-1.4427 So, #3-1.4435/316L, #4-316LUgim and #5-316L Val.

According to Zanotto et al., the test has limitations, it becomes non-discriminating in case of steels with excellent corrosion resistance [51].

In case of steels #8, #10, #6 and #17, the test, carried out under the same experimental conditions, showed no signs of corrosion of the transversal or longitudinal surfaces, similar to sample #3 (Figure 6).

**Figure 6.** Pitting test results of the transverse and longitudinal surfaces for various grades of steel alloys (0.5 M FeCl3 test medium at 50◦ for 2 h).

The results obtained are presented in Table 6. In general, the transverse surfaces were corroded with the exception of steel #3. Examination of steel #3 did not reveal any traces of corrosion either in the cold-worked state.


**Table 6.** Observations after the salt fog test (samples tested in annealed, cold-worked state).

\* T: transverse surface, \*\* L: longitudinal surface, with respect to the rolling direction.
