PSI - Issue 19

Lloyd Hackel et al. / Procedia Structural Integrity 19 (2019) 346–361 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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crack on the left side) is in the range of 1-plus inches (25 mm) in length. This crack is running parallel to the weld direction and in the heat affected zone. This is the same crack as seen under higher magnification in Figure 12 where it is clear that additional cracks were forming in this un-peened area both along the weld direction and transverse to the weld. Figure 13 shows additional cracks starting on the opposite side of the exposed area. This test confirmed that an un-peened panel would crack in this harsh MgCl2 environment in less than 7 days.

Figure 11. Area exposed to MgCl 2 encompassed by distinct ring. Major crack has become white after exposed to air and drying out. Crack length is on the order of 1-plus inches in length.

Figure 12. Magnified view of area of 316 stainless steel test panel after 7 days exposure to MgCl 2 at 155°C. Large crack length is of size 1-plus inches. Cracks predominate in heat affected zone.

Figure 13. Magnified view of opposite side of weld heat affected zone of 316 stainless steel test panel after 7 days exposure to MgCl 2 at 155°C. Cracks predominate in heat affected zone.