Page 383 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

CORROSION DAMAGE, DEFECTS, AND FAILURES 361

Figure 5.46 Fracture pipe clamp and fasteners. (Figure originally published in Reference 26.
Reproduced with permission of the Canadian Institute of Mining, Metallurgy and Petroleum.
www.cim.org.)

1 mm

Figure 5.47 Transgranular cracking in failed clamp (19).

The pipe joint was leaking steam and water prior to the failure, and the chemi-
cal analysis of the leaking steam and water showed 10% sodium chloride. The high
chloride and the highly stressed austenitic stainless steel with atmospheric oxygen
created an ideal chloride stress-corrosion cracking (SCC) environment.
The failure could have been prevented by joining the steam piping by welding
instead of using high-pressure clamps. It can be stated that the root cause of the failure
is human error in choosing stainless steel.

Failure of a Steel Coal-Conveyor Drive Shaft This failure was because of a
transverse crack that passed through the right keyway near the center of the keyway
(Sastri et al. (19), p. 499, Fig. 7.50). The shaft was cut to open the crack and expose
the corroded mating surfaces. Two sets of crack arrest marks were concentric to each