Failure Analyses

Final Report Issued on Fatal New Zealand Cruise Ship Blast

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.

MIC Failure of Type 316L Seawater Pipeline

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.

Failure Analysis: In-Situ Combustion Injector Well Tubing Failure

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 future failures.

Failure Analysis of Pyrolysis Furnace Transfer Line Tubes

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 Failure of a Copper/Nickel Overhead Condenser Bundle

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).

Unusual Occurrence Causes Leak in High-Pressure Underground Gas Pipeline

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.

Failure of Glass-Reinforced Epoxy Material Piping Components on an Offshore Platform

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.

Failure of Electrolyte Pipelines in a Chlorine and Alkali Factory

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.

Failure of an Air Inlet Header of a Secondary Reformer

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.

Erosion-Corrosion Failure of a Spiral Heat Exchanger

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.

Using Industrial Computerized Tomography for Corrosion Investigation

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.

Microbiologically Influenced Corrosion in a Copper Tube Chiller

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.

Formicary Corrosion of Cupronickel Tubing

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.

Failure Analysis of a 30-in Subsea Oil Pipeline

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.

Oil Refining Heater Tube Failures from Internal Melting

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.