In a new report on corrosion inside underground storage tanks storing diesel fuel, the U.S. Environmental Protection Agency found moderate or severe corrosion could affect metal components inside both steel and fiberglass tank systems.
Average annual salaries in 2016 are reported for corrosion professionals in the United States, Canada, United Kingdom, and Europe. A slight gain was seen for the United States and United Kingdom, while a larger increase was recorded in Canada.
Corrosion can either take place locally to form a pit or crack, or it can extend uniformly across a wide surface. Proper surface analysis of the corroded sample is vital for evaluating corrosion characteristics and mechanisms, so the best materials, protective coatings, and corrosion-control measures can be selected.
Corrosion professionals in North America and Europe have experienced another year of continued growth in career opportunities and salary levels, according to the 2015 Corrosion Career Survey conducted by Materials Performance magazine.
To successfully communicate the wide variety of corrosion-related issues affecting corrosion professionals today, MP is actively encouraging corrosion control professionals worldwide to submit technical articles to share their corrosion-related experiences with over 36,000 NACE International members around the globe.
This article presents findings of a failure investigation on a separator vessel in an ammonium nitrate (NH4NO3) plant. The super duplex stainless steel vessel leaked due to stress corrosion cracking initiated in the heat-affected zones of welds exposed to the NH4NO3 solution at ~180 °C.
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.
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.
This article discusses a field background search,
macro- and micro-corrosion morphology analysis,
and material testing of corroded premium
connection downhole tubing. Tubing failure was
caused by erosion-corrosion from highly disturbed
liquid and high shear stress at the couplings.
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.
This article describes the findings of a detailed
failure investigation on a UNS S32750 super
duplex stainless steel vinyl chloride stripper vessel
that experienced cracking at nearly half of the
welds. The cracking was identified as Type A
“active-passive” stress corrosion cracking, which
initiated on the inside of the vessel at both the
circumferential and longitudinal welds.
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.
The academic side of failure analysis was presented
in Part I of this article. This included 1) steps in conducting a failure analysis, 2) typical tools, and 3) theory of crack propagation. This article provides several case studies demonstrating the use of these techniques.
This study investigated the failure of a 15-5 PH
(UNS S15500) precipitation-hardened stainless
steel stem when installed in a 5 1/8-in (130-mm)
hydraulic surface safety gate valve working in a sour
gas environment. The results indicate that the
fracture failure was caused by sulfide stress
cracking, which progressed transgranularly
in the martensitic matrix.
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.