New Zealand’s Transport Accident Investigation Commission published its final report on a fatal accident involving the massive Emerald Princess cruise vessel, in which a nitrogen cylinder burst and fatally injured a nearby crew member.
A Type 316L stainless steel (SS) (UNS S31600)
pipeline carrying seawater suffered pitting and
leakage within a few years of installation. Visual
examination revealed penetrations and shallow pits.
Electron probe microanalysis results indicated a
decrease in chromium concentration within the pit
and in the iron concentration at the pit periphery.
Microbial investigation confirmed the presence of
sulfate-reducing bacteria and chromium-,
manganese-, and iron-oxidizing bacteria.
Severe plugging of in-situ combustion injector
wells was found within 15 months of their
commissioning in an on-land oil field in western India.
Laboratory investigations were made to establish the
cause and identify remedial measures. The tubing
sections in the vicinity of the combustion front were
exposed to an aggravated oxidation environment followed
by moisture and oxygen intrusion through corrosion
product. This triggered conversion of magnetite into
porous, nonprotective hematite. The corrosion inhibitor
treatment in the wet phase was found to be ineffective.
A large amount of loosely bound corrosion product
accumulated at the bottom of the hole during air/water
injection. This plugged the well. Suitable well completion
for the operating conditions was designed to prevent
Transfer line tubes of an ethane pyrolysis furnace, operating at 850 ±20 °C and 1.0 atm pressure, developed longitudinal cracks after less than one third of their expected service life. The tubes were constructed of Fe-based UNS N08810 alloy with a wall thickness of 10 mm. Metallurgical evaluation revealed that the mode of failure was high-temperature carburization attack leading to intergranular cracking. The cause of failure was overheating, likely to have occurred during decoking operations. Better control of furnace temperature was recommended to avoid overheating. Alternatively, a wrought alloy capable of developing highly protective aluminum oxide (Al2O3)-base scale such as Ni-based UNS N07214 could be used as a replacement.
Rapid and unexpected failure of a CuNi bundle of
a stabilizer overhead condenser occurred where
an Al-brass bundle showed chemical resistance for more
than 20 years. An investigation revealed that the intergranular
attack/cracking of the cupronickel tubes was
caused by attack of a wet hydrogen sulfide (H2S)-
containing medium. Literature indicated that cupronickel
is much more susceptible to attack by wet H2S than Al-brass.
Cupronickel is unsuitable as tube material in
overhead systems containing significant amounts of H2Sand ammonia (NH3).
A gas leak was detected on a 56-in (1.4-m) crosscountry
gas pipeline from a small orifice on the
bottom of an indentation. The pipeline had an epoxy
primer and a hot polyethylene coating, and was only four
years old. Metallurgical tests on the hole and theoretical
calculations indicated that the pipeline had been
penetrated by a bullet before being coated. This may be
the first such case recorded, and would have been difficult
to prove if an explosion had taken place.
Glass-reinforced epoxy (GRE) is a synergistic
combination of two or more materials with a
reinforcement of E-glass fiber. The brittle nature of the
material demands careful handling during transportation,
fabrication, and installation. This article describes the
analysis of components that failed in a GRE piping system.
The failed components were examined through
destructive and nondestructive tests. The failure modes
and analysis revealed that the combined effect of
manufacturing defects and installation practices caused
various types of failures.
The failure of electrolyte pipelines made of
1Cr18Ni9Ti steel in a chlorine and alkali factory
was investigated. Corrosion was caused by localized
attack from the accumulation of chloric ion and hydrogen
induced by welding. The corrosion resistances of two
alloys in chlorine and alkali industrial environments were
determined. It was suggested that Type 304 stainless steel
(SS) (UNS S30400) or Type 316 SS (UNS S31600) be
substituted for 1Cr18Ni9Ti steel.
Failures from the overheating of components may
occur from short- or long-term exposure. Failures
may cause plant shutdown, which in turn will have
economic implications. Pipes that carry gases at high
operating temperatures are susceptible to this type of
failure. The more destructive ruptures occur at pipe metal
operating temperatures well above the ASME oxidation
limits of the material. This is typically above the eutectic
transformation temperature for any selected alloy. This
article presents the general aspects of overheating
failures and a case study of a recent investigation of an
air inlet header failure.
This article discusses a failure on a Type 316
stainless steel (UNS S31600) spiral heat
exchanger. The failure occurred just five months
after the equipment had been put into service. The
study showed that degradation occurred from
erosion-corrosion in the vicinity of the spacers
between the metal sheets.
Industrial computerized tomography (ICT) was used
to investigate the corrosion failure of a chlorine
condenser tube, shell, and welding. The ICT analysis
indicated that corrosion was most serious where the
tube and shell were welded together. This work also
showed that ICT can be a valuable tool in corrosion
analysis because it can detect gaps or interstices, and
quantify their size, shape, and position.
The increased use of recycled water has led to the
need for an effective water treatment program to
prevent microbiologically influenced corrosion
(MIC). This article describes an investigation of
copper tubes in a chiller that failed from MIC
because of a poor water treatment program.
The occurrence of formicary corrosion, or ant-nest
corrosion, has been primarily reported throughout
the heating, ventilation, and air-conditioning
industry. Until now, the presence of formicary
corrosion has been limited to refrigeration-grade
copper (99.99% Cu). A failure investigation
has attributed leaks in cupronickel
tubing to formicary corrosion.
This article presents the failure investigation of
internal pitting corrosion on a 30-in (0.762-m)
diameter subsea oil pipeline in western offshore
India. Detailed laboratory and analytical studies
were made on the failed sample to establish the
cause and mechanism of failure. This article
describes the analysis methodology, the probable
corrosion and failure mechanism, and recommended preventive measures.
The mechanisms that usually limit the life of tubes
in oil refining heaters are excessive wall thinning
from corrosion, erosion, or creep. Tube selection for
this service is usually based on material that will
withstand these factors. It is not uncommon,
however, to experience tube failures from
operational factors. This article describes cases
where flow restrictions within tubes led to
melting from the inside out.