Comprehension of the sulfidation corrosion reaction and the behavior of different materials in H2-free and H2/H2S environments is imperative for oil refineries.

Processing renewable feeds presents a blend of damage mechanisms for which existing hydroprocessing equipment may not have been designed. No “one-size-fits-all” approach exists to evaluate all the specific degradation concerns for a renewables...

This article concludes the series on microbial-induced corrosion by demonstrating the importance of microbe mitigation through two case studies.

Ferritic materials change in toughness as a function of temperature, but the change is non-linear and happens at different temperatures for different materials.

Part 3 of this series provides pragmatic strategies for mitigating high-temperature creep damage in typical pressure component alloys.

Our proprietary furnace tube inspection system, FTIS is an ultrasonic inspection technology capable of rapid, automated fired heater coil inspection in refinery fired heaters. The data captured by our furnace tube inspection system is...

General guidance to provide a foundation to complete a solid inspection plan for sulfide stress cracking (SSC) as a result of the wet hydrogen environments.

Part 2 of this Damage Control series on high-temperature creep discusses engineering evaluation methods that can be used to predict the remaining creep life of components. Comparisons between the Larson-Miller Parameter and the MPC Omega are offered.

Worldwide, microbial-induced corrosion and biofouling are a challenge to the oil and gas industry. Part 1 of this series reviews simple methods for identifying post-construction MIC damage, biofouling, and mitigation and the microbes that cause it.

A focus on typical damage morphology and inspection methods used to identify and characterize high-temperature creep including examples of creep damage and in-service failures to offer insight into this complex damage mechanism.

This final installment of a 3-part series on SCC mitigation will provide practical, actionable steps to improve long-term equipment reliability through design, fabrication/welding, heat treatment, maintenance/repair, and process operating practices.

AET is a powerful, non-intrusive inspection technique to verify the structural integrity of pressure vessels, spheres, high-temperature reactors and piping, coke drums, above-ground storage tanks, cryogenic storage tanks, and more.

Shedding some light on the realities of hydrogen diffusion in the context of repair planning and equipment management and helping answer the age-old question, “Do I have to bake this out?”

As one of the simpler API 579 FFS assessments, there are relevant criteria to check that are necessary to assess and evaluate laminations.

Part 2 of the three-part series on stress corrosion cracking (SCC) that examines common engineering and FFS methods that can be leveraged to understand and evaluate the propensity for an existing form of SCC to lead to loss of containment.

Of the nearly 70 damage mechanisms listed in the latest edition of API RP 571, the highest FEMI risk may be the ones that are highly localized in nature and, therefore, the hardest to find.

This study found that a machine learning model was able to predict degradation rates for a hydrocracker unit more accurately and with a smaller margin of error compared to current industry practices.

Auto-refrigeration can impose low temperatures onto process vessels and piping causing them to be at risk of brittle fracture, the sudden break-before leak phenomena that can result in catastrophic rupture of the equipment.

This article provides an overview of some of the more common forms of stress corrosion cracking (SCC) with a focus on effective inspection methods for detecting these forms of cracking.

This article describes HTHA predictive modeling advances that are designed to demonstrate a direct integration with inspection such that modeling and inspection can be leveraged together in a way never done before.

Within one unit, TriLat combines the power of two probes containing three angle beam sets to identify and quantify cracking at early stages. The result is inspection speeds up to ten times faster than traditional AUT systems, depending on probe size.

This edition of Damage Control will offer practical steps to mitigate different forms of wet H2S damage and help to minimize long-term inspection and maintenance costs related to wet H2S damage.

Establishing a proactive touch point corrosion integrity management program using engineered on-stream line lifting is a safe and effective means of mitigating unplanned downtime and related safety and potential environmental hazards.

FFS assessment techniques are applicable to a wide range of damage types: LTA's, cracks, creep damage, dents, and more. These are very powerful analytical tools that often allow operators to not only keep the plant running, but to keep it running...

This issue of Damage Control offers a perspective on how to assess the different forms of wet H2S damage using modern FFS and computational analysis techniques with the safe operation of damaged pressure vessels, piping, and associated components.

This article presents two case studies that show how having a holistic approach, along with the right technology and experience, is essential to identifying smaller damage mechanisms like fretting in fired heater coils.

This article summarizes the fundamentals of wet H2S-related damage mechanisms, offers some practical inspection guidance, and reviews a notable industry failure caused by different forms of wet H2S damage.

This article discusses how composite materials can be used to mitigate light CUI damage and/or repair and restore structural strength to the affected piping system.

Recent advances in UT technology now allow for inspection and continuous monitoring of sulfidic corrosion to be undertaken while the components are on-stream, at temperature, with high-resolution thickness data.

Equity Engineering Practices® (EEPs) are a collection of design and maintenance focused corporate standards that include >850 engineering standards, and >300 piping classes. Enhance your mechanical integrity programs, improve equipment...

The scope of the subject case study reviews an inspection and corrosion control assessment conducted on subsea flowlines and includes evaluating the flowlines’ associated inspection programs and identifying all available NDT technology solutions.

Practical steps to mitigate corrosion under insulation (CUI) damage on fixed pressure equipment and commentary on common mitigation techniques and good engineering practices for external insulation or fireproofing system design and application.

Hydrogen-induced damage mechanisms have been studied endlessly, leading to changes in equipment design and development of new inspection practices. However, the highly localized nature and difficulty of detection of HTHA add additional complexities.

It can be challenging for failure analysts to present complex information to audiences that don't the same knowledge on specialized subjects. Sometimes, failure mechanisms can be summarized with images that can tell the whole story...

In this article, FFS assessment methods are summarized and practical guidance is offered for qualifying CUI damage on carbon and low-alloy steels.

Training options to meet your needs. E²G contracts with API to deliver training programs for FFS, Risk–Based Inspection, Damage Mechanisms, and Pressure Relieving Systems. ETI and Customized Training offers specialized courses based on industry...

This article provides insights into the AIV damage mechanism, reviews approaches to calculate the probability of AIV failure in piping, provides design practices to prevent AIV failure, and introduces a RBI approach to evaluate risk of AIV failures.

Corrosion under insulation is a form of external corrosion that is caused by trapped water on insulated surfaces. It is an industry problem affecting equipment in the oil and gas, petrochemical, specialty chemical, fertilizer, and related industries.

The first two parts of this series covered the basics of fracture mechanics and how the FAD is interpreted. This article touches on a few practical points regarding the application of fracture mechanics in a plant environment.

Thermal fatigue, a specific form of fatigue driven by varying metal temperature gradients and ensuing differential thermal expansion, is generally most effectively mitigated by reducing the severity of metal temperature gradients.

This article discusses the header specification, design, fabrication, and inspection processes to identify where opportunities were available to proactively address the vulnerabilities that resulted in the header rupture.

What do you need: CONSULTING - Subject matter experts, consultants, or team of highly skilled engineers to help solve my problem. SOFTWARE - My team requires software, products, or resources that will solve the problem. TRAINING - I require...

Conventionally, three primary fatigue analysis methods have been used to estimate fatigue life; these are the stress-life (S-N) approach, the strain-life (ε-N) approach, and the fracture mechanics (crack growth) approach.

Every fitness-for-service (FFS) assessment must have a well-defined acceptance criterion. For many damage mechanisms, it’s the “remaining strength factor” (RSF). But for crack-like flaw assessment, it’s the Failure Assessment Diagram, or FAD.

Fracture mechanics is a branch of engineering that describes the behavior of cracks – how they grow and when they fracture. Fracture of cracks is particularly dangerous because it can happen without warning under normal operating conditions.

Understanding asset integrity and its management framework is important to sustaining the integrity of assets in the oil and gas industry. This article will discuss eleven primary elements that make up an asset integrity management program.

This article reflects the first in a series on damage mechanisms that will appear in this recurring Inspectioneering column entitled “Damage Control.” The inaugural topic discussed in this column is thermal fatigue.

In today's chemical and refining industries, sustained long term reliability of facilities is critical to profitability and competitiveness. In fact, history shows that differences in operating expenses between best-in-class refineries, and poor...

Ideally, all valves should work when needed; but the truth is that valves fail. This article discusses the common failure mechanisms that affect valves as well as what inspectors should look for during an inspection.

Assessment procedures in API 579 are organized by damage mechanism. But what happens when different damage mechanisms are in play since the evaluation criteria may not be compatible?

Nelson curves, which are the foundation of the industry’s HTHA programs, can be tied to mechanistic models from several sources, allowing the recreation of Nelson curves for different operational histories and time durations.

The purpose of this article is to describe some of the pitfalls that operating sites have encountered while trying to implement a program of IOWs in accordance with the guidance in API RP 584, plus how to overcome those pitfalls.

This article addresses two failure events where inadequate attention to thermal fatigue led to premature equipment failure while specifying guidelines to help prevent such failures that can be a part of a plant's inspection and maintenance programs.

Inspectioneering and API have teamed up to create the Mechanical Integrity Professional Initiative. The goal of this project is to raise the benchmark on industry knowledge and develop the next generation of SMEs. We believe that equipping MI...

There are many sources and occurrences of metal fatigue in the chemical and refining industries. They range from low-cycle thermal stresses in an FCCU, to the relentless pressure cycling of a PSA, to the ultra-high cycles of a rotating pump.

We’re excited to announce a new section of our website that is dedicated to equipping inspectors with greater knowledge and proficiency across various subject matter areas.

A damage mechanism review, or DMR, is a structured process performed by a qualified team to gain a better understanding of unit operations, corrosion loops, materials of construction, and potential damage types and locations.

A significant number of pipeline failures due to external or internal corrosion have resulted from MIC, some with catastrophic consequences. This article demonstrates a three-step failure analysis process used to investigate the failure mechanism.

Gasification technology has emerged in oil and gas due to the high combustion energy of Syngas and less environmental concerns than flue gas. This article discusses proper inspection and corrosion monitoring techniques for gasification units.

Becht’s industry-leading Corrosion and Metallurgical experts are here to help with significant owner-operator experience covering the refining, petrochemical and chemical industries. This expertise is leveraged to help our clients become more...

Inspectioneering and PinnacleART recently hosted a roundtable discussion for a select group of mechanical integrity experts to discuss strategies for managing corrosion under insulation and corrosion under pipe supports, a.k.a. touch point corrosion.

A well-implemented and managed reliability program incorporating RBI, DMR, and IOWs can identify potential damage mechanisms, optimize maintenance and inspection activities, reduce risks, and improve the governance in managing Ethane Crackers.

This article provides a summary of the 2019 API Inspection & MI Summit keynote address, which offers a past, present, and future outlook on fixed equipment mechanical integrity from an industry professional with 50+ years of experience.

The 2019 API Inspection and Mechanical Integrity Summit will be kicking off later this month in Galveston, TX. This four-day event will begin with 14 high level training courses offered Monday, January 28th, and then a top notch conference and...

This article discusses the advances in NDE that have given owners increased confidence on how to assess equipment integrity in HTHA service providing risk prioritization of equipment as well as providing the ability to make more reliable...

TEAM’s integrated touch point corrosion program manages all aspects of the integrity process from screening for damage to permanent repair assuring integrity – every time. TEAM’s unique turn-key approach to touch point corrosion integrity...

Corrosion control knowledge and resources can be applied more effectively through the development and implementation of a corrosion management system (CMS). A CMS better-connects management system elements to the process of managing corrosion...

This article presents a case study from a Middle Eastern refinery that explores a heat exchanger that failed unexpectedly after five years in service. There are multiple initiators that can cause under deposit corrosion (UDC) in heat exchangers in...

There is concern in the industry over recent findings of reduced toughness fittings and flanges at risk of brittle fracture. This article provides an overview; possible contributors; measures taken to address; and a proposed FFS approach to address...

HTHA of hydrogen-containing equipment can be prevented with appropriate material selection and fabrication, appropriate welding procedures, regular inspection of equipment using proven, effective technologies and equipment operated by qualified...

Hot spots – localized areas of overheating in pressure equipment – can lead to deformation or even loss of process containment. It is important to understand the effects of elevated temperature caused by hot spots on the mechanical integrity of...

Statistical techniques are meant to complement the work of SMEs and can provide deeper insights into the inspection data collected as part of a reliability program. Pinnacle has combined traditional methods, expertise, and Machine Learning to...

Sea water corrosion and erosion issues can affect almost all commonly used metallurgy in a refinery or petrochemical plant. This brief article explains the dangers behind sea water used in plant cooling systems and discusses several metallurgical...

Given the concern throughout industry regarding the potential for brittle fracture failures, PWHT guidance to address potential issues arising from the recent changes in PWHT code requirements for carbon steel is examined in this article, and...

Thanks to the development of documents such as API RP 571 and API RP 586, as well as the emergence of qualification demonstration testing, we can align NDT techniques and inspection strategies better than ever. This article examines this progression...

Fired heaters are among the most critical equipment in refineries and chemical plants. This article provides an overview of what a fired heater tube mechanical integrity program should include.

Failure analysis of piping that has experienced corrosion damage provides operators with valuable information needed to prevent future failures. Effective processes and procedures are essential when investigating the cause of corrosion on pipelines...

Pinnacle's data-driven reliability framework ensures the right data is fueling the right intelligence, helping you make confident, strategic decisions.

Effective condition monitoring location selection is a key component of a best-in-class mechanical integrity program. Learn how moving beyond traditional qualitative approaches to optimized CML selection can reduce risk and maximize the value of...

Read a firsthand account of how organizing Process, People, Plant, and Performance can reveal breakdowns in your corrosion management practices and drive down corrosion related leaks.

Myths, challenges, and good practices related to process piping integrity management activities that help inspection and maintenance managers make the right decisions to develop cost-effective piping inspection plans without compromising the...

This article discusses the use of the RBI methodology supplemented by a well-designed IOW program to assess and manage aging in fixed equipment and piping in hydrogen generation units.

This article summarizes a comprehensive survey conducted by the Research & Development Center (R&DC) of Saudi Aramco to understand top corrosion damage mechanisms experienced by its operating onshore surface facilities.

Download Pinnacle's Economics of Reliability Report - Refining to see how reliability is affecting profitability.

In this article, the roles and responsibilities of the corrosion and materials SME will be outlined as I see them, fully recognizing that there is probably no one person out there with all the knowledge and skills suggested herein.

Historically, if asked when or how likely an austenitic series stainless steel component is to crack, the usual answer was “very” or “maybe” or, later, “I didn’t see that coming.” With API’s new risk assessment methodology, the...

Beyond the financial hits, undetected degradation from corrosion can also lead to critical safety risks. To effectively manage mechanical integrity, organizations need reliable methods of identifying the current states of corrosion occurring within...

Detecting, quantifying, and sizing indications characterized as a “crack" in critical equipment have long been the global benchmark of asset integrity programs. Therefore, the increased precision that inspection programs obtain using advanced...

Seasoned and knowledgeable inspectors are becoming harder and harder to keep. But using some of the industry documents in a smart way, inspectors with less experience can perform like an inspector with many more years of experience and even develop...

Traditional pressure vessel inspections often require taking assets out of service. However, MISTRAS’ Non-Intrusive Inspection (NII) programs provide data as good or better than internal inspections, while assets remain in service. NII is...

Over 20 years ago, in the January/February 1996 issue of Inspectioneering Journal, we invited readers to participate in a brief survey concerning industry and non-industry topics. We recently unearthed the results to this survey and I thought our...

Experienced material specialists are in short supply and high demand these days. So if you are lucky enough to have one at your disposal, how can you squeeze the most out of that opportunity?

This article summarizes a recent finite element analysis (FEA)-based study that employs creep simulation techniques to investigate the elevated temperature response of piping with peaked longitudinal weld seams.

To ensure the mechanical integrity and fitness-for-service (FFS) of equipment, facility managers, reliability engineers, and inspection technicians must understand the HTHA damage mechanism.

Understanding the common factors that promote corrosion threats in the oil and gas value chain helps operators create effective inspection strategies.

Traditional, paper-based inspection processes can prevent plants from being as effective as they can be. By digitalizing your mechanical integrity process and data with MISTRAS Digital®, plants have realized up to 75% gains in IDMS data entry and...

If we could measure, understand, mitigate, and most importantly, control corrosion, we can do a better job of keeping the product in the pipes. To accomplish this task, we needed to know what is causing the corrosion and how to control it.

This post is based on an article from the September/October 2008 issue of Inspectioneering Journal by Richard Green at Accurate Metallurgical Services. You can find the original article here.

This article provides background on HTHA, discusses some current developments in HTHA inspection and mitigation, and describes how one refiner is instituting an HTHA risk management plan for its refineries along with challenges they have encountered.

Maintaining mechanical integrity for aging power boilers can be challenging. This article provides a case study on how mitigating one damage mechanism led to the discovery of another, and how refinery engineers collaborated with industry experts to...

A small leak from top tubesheet-to-tube welds prompted further inspection of the 1¼Cr- ½Mo Ammonia Converter Boiler Feed Water (BFW) Exchanger during a planned shutdown. Further cracks were identified in the top channel to tubesheet butt weld that...

Antea delivers highly flexible risk-based asset integrity software with 3D Digital Twin integration to optimize maintenance, reduce risk, and improve mechanical integrity for oil and gas, power generation, and chemical plants and facilities....

I've crunched some numbers and have come up with the three most popular damage mechanisms, based on the activity of our readers, that Inspectioneering publishes information on.

As any refining or petrochemical plant manager knows, corrosion can occur on insulated piping at any facility. CUI has been a major challenge for the petrochemical and refining industries since the first pipelines were insulated with wrappings.

AE monitoring has been done for HIC affected vessels, with limited success. The limitation, which greatly affects the confidence level of results, is that traditional AE testing stresses, i.e. Kaiser affect overpressure and felicity effect types of...

High temperature sulfidation is probably the most well- known corrosion mechanism in the oil refining industry because it occurs in large sections of the refinery.

Fired furnaces in the petrochemical and refining industry are critical pieces of equipment that can have a major impact on process unit safety, reliability, and economics. They are complex pieces of equipment, where tubes and other pressure boundary...

Pro-Surve recently invested in the latest portable Higher Order Modes Clusters (HOMC) Guided Wave Testing tool, a new concept for the inspection of inaccessible regions using short-range guided waves. Inspection is carried out from the accessible...

Last week we mentioned three important tips to consider when addressing high temperature hydrogen attack (HTHA). This week, we'd like to provide the reader with a few helpful resources that deal with the topic of HTHA.

One of Inspectioneering's editorial themes this month is High Temperature Hydrogen Attack (HTHA). It is a highly contentious issue that the industry is still struggling to fully understand.

Small bore piping is present in many variations throughout numerous industries. This article will address an incident involving a small bore piping failure that occurred on a 140,000 BPD crude distillation unit in the refining industry.

On August 6, 2012, a piping failure occurred in the #4 Crude Unit at the Chevron U.S.A. Inc. refinery in Richmond, CA. Chevron U.S.A. would like to share some potentially significant preliminary information regarding the incident.

We have recently learned of one organized joint industry project (JIP) that was announced at the Spring 2012 API Refining meeting. As information has become available we have decided to present it to our readership.

Tri-Lateral Phased Array is a novel robotic phased array ultrasonic testing technique for the on-stream inspection of fixed equipment in wet hydrogen sulfide (H2S) service. TriLat identifies and quantifies wet H2S damage in the base metal of...

What I am primarily concerned with, in this article, is erosion corrosion control. Now, what is erosion corrosion? Well, no matter how you might look at it, erosion corrosion involves the degradation of the material by some mechanical action, in...

High Temperature Hydrogen Attack (HTHA) is a long known and still occurring degradation issue for fixed equipment construction materials in the hydrocarbon process industry where hydroprocess plants (hydrogen plus hydrocarbons) are in service....

The following references are from the American Petroleum Institute. They are widely used in the petroleum refining and petrochemical industries for managing equipment in HTHA service and are available in the public domain.

You're at 32,000 feet in an airplane when you look out the window. You observe the wing of the jet moving up and down with the turbulence, like a child bending a coat hanger over and over again until the wire fractures into two pieces. You wonder...

A myriad of issues need to be considered before welding to or repairing weld overlayed or clad equipment. (By clad we mean roll-bonded or explosion bonded, i.e. basically 100% metallurgically bonded, and not a loose or seam-welded liner, e.g., not...

The OmniScan™ X3 64 phased array and TFM flaw detector is equipped with enhanced phased capabilities and even faster TFM. The rugged and portable instrument features powerful 64-element probes with a 128-aperture TFM.

In previous parts of this series, I have covered many corrosion and degradation issues, some environmental cracking diseases, metallurgical degradation mechanisms, issues associated with welding and some external corrosion problems. In part 14,...

As noted in the discussion on delayed cracking, when the steel contains hydrogen as a result of service exposure (or corrosion, or high temperature - high pressure hydrogen processing) then a hydrogen bake out may be needed to avoid cracking...

After a pressure equipment or piping failure, it’s not uncommon to find out during the failure analysis part of the investigation that the failure initiated at a welding flaw of some sort.

Temper embrittlement is another form of metallurgical degradation resulting from exposure of susceptible low alloy steels to higher temperature ranges, usually in service, but can occur to some extent even during heat treatment. And, once again, if...

Strain-aging problems are another form of metallurgical degradation and thankfully are not very common and becoming less so; but since strain-aging does still occasionally occur, it still makes the list of one of the “99 diseases of pressure...

Ethos has assembled a team of experts who apply what they learned through years of process safety experience in the industry and dealing with OSHA and EPA. Click here to learn more about our services.

Another form of metallurgical degradation at higher temperatures is called sigma phase embrittlement. As the name implies, a metallurgical phase change occurs in some stainless steels when they are heated above about 1000F (540C).

Titanium (Ti) hydriding is another somewhat unusual metallurgical degradation phenomena that can result in brittle fracture. Unlike many other steel embrittlement phenomena, this one most often occurs in thin wall Ti tubes that have been selected...

Metals will slowly deform under stress and higher temperatures by the mechanism known as creep. The amount of creep deformation that will be experienced is highly dependent upon the level of stress, level of temperature and material properties....

Spheroidization is a rather technical term that describes a metallurgical aging phenomena that results in loss of mechanical and creep strength. It occurs when carbon and low alloy steels are exposed to temperatures in the range of 850F - 1400F...

This bulletin is part of a series of WRC Bulletins that contain the technical background and other information to evaluate damage mechanisms in various industries to facilitate the use of API 579. These bulletins, shown below, will be updated based...

Whether you decide for a Computed Radiography scanner with flexible imaging plates or a flat panel detector with the fastest imaging, or even combine the advantages of both technologies, DÜRR NDT's innovative systems offer high reliability and the...

Carbon dioxide (CO2) corrosion is most typically found in boiler condensate return systems that are not adequately treated with corrosion inhibitors (typically amines). Dissolved CO2 in condensate forms carbonic acid (H2CO3) which corrodes steels...

Boiler feed water (BFW) corrosion is mostly the result of dissolved oxygen in the feed water, but is also related to the quality of the BFW and the quality of the treatment system.

Cooling water (CW) corrosion may be the oldest form of corrosion in the petrochemical industry, yet the industry still struggles with it for two primary reasons.

MIC is caused by biological growth, i.e. organic slime (typically bacteria, algae, and fungi) in water under low flow or stagnant conditions. The industry experiences it in cooling water systems, piping, vessels and storage tank bottoms where the...

Most all flue gases produced by the combustion of fuels contain contaminants that can condense into acid droplets. The amount of contaminants will determine the concentration of the acid droplets.

Artificial Intelligence (AI) is transforming the inspection process, enabling automatic defect detection and even higher data integrity. With our DIMATE PACS software, we help you optimize your inspection workflows and benefit from the use of AI...

Polythionic Acid Stress Corrosion Cracking (PASCC) is an affliction of many refineries processing sulfur containing feedstocks, and since that is the norm these days, most refiners reduce their susceptibility to PASCC by selecting resistant alloys...

Hydrogen stress cracking occurs when corrosion from acids like wet hydrogen sulfide or hydrofluoric acid (HF) cause atomic hydrogen to penetrate hardened or higher strength steels and cause stress cracking.

HTHA falls into multiple categories of corrosion mechanisms, including environmentally assisted cracking, hydrogen assisted cracking, and high temperature degradation. Sometimes HTHA is confused with low temperature hydrogen cracking mechanisms...

Corrosion fatigue is closely related to mechanical and vibration fatigue cracking, except that it is initiated and accelerated by a corrosion mechanism, especially one that gives rise to pitting, from which cracks often initiate. But that...

Accounts with shop validation on carbon steel samples prior to field trials, on an in-service C 1/2 Mo vessel, were reported at a recent industry conference. The studies were successful in the laboratory and appear to make sense in field trials on a...

Traditional inspection methods used to detect internal corrosion and corrosion under insulation (CUI) in piping and pipeline assets can be time-consuming and costly. With ART, you’ll discover CUI detection best practices that can help save you up...

Corrosion from HCl is a significant problem in many refining and chemical process units, and often the materials solution to HCl corrosion is rather expensive, since the lower cost, more available alloys are usually not resistant to most...

Corrosion in the refining industry from HFA is not as widespread a problem as it is with HCl because it is only associated with HF Alkylation Units, which are usually fairly carefully controlled in order to avoid potential for a toxic HFA cloud...

Problems with naphthenic acid corrosion (NAC) are nearly as old as the refining industry. The first paper on the topic that I knew about was written by one of my early industry supervisors over 40 years ago.

Unlike NAC where we’re still on a learning curve, the knowledge of corrosion by sulfuric acid has not changed much in the last quarter century, and there are many good references for it included in API RP 571.

Corrosion from phosphoric acid is another “old knowledge” corrosion issue that effects only a few processes in the chemical and hydrocarbon process industry.

Catastrophic oxidation can occur when certain contaminants are present in a high temperature environment, i.e. inside furnace fireboxes, in our industry. Those contaminants are typically vanadium pentoxide with sulfur oxide or sodium sulfate.

Though oxidation and sulfidation are quite prevalent high temperature corrosion mechanisms in many of our process units, we now come to a few that are not very common, but still deserve some attention to make sure they don’t lead to...

Metal dusting is simply a severe form or extension of carburization in which the extensive carbides that form as a result of carburization lead to grains of metal falling out of the tube or piping and being swept away by the process...

Chloride cracking of austenitic stainless steels (300 series SS) is an off-shoot of CUI, and there’s nothing really magical about it. If you have insulated solid stainless steel equipment operating in the CUI temperature range you are likely to...

For purposes of this article, external (atmospheric) corrosion is what afflicts process equipment and structural members that are not insulated and exposed to moisture associated with atmospheric conditions, ie rain, condensation from humidity,...

Soil corrosion (underground corrosion) is another one of those extensively researched and documented types of corrosion, since so many pipes and pipelines are buried and nearly all storage tanks rest on the soil. An entire industry/ technology is...

CUI may be the most well known and widespread corrosion phenomena in our industry. It’s also one of the most difficult to prevent because by and large no matter what precautions we take, water eventually gets into the insulation and begins...

API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry

Casting defects are an age old problem for our industry that seems to be getting worse as foundries in the older industrialized world shutdown for economic reasons.

Speaking of stress raisers, they are another insidious type of flaw that can and do lead to equipment failures. Stress raisers (aka stress intensification sites) can be mechanical or metallurgical notches. Undercutting, physical weld flaws,...

When we specify that some equipment (vessels, flanges, fittings, etc.) be overlaid with a corrosion resistant alloy, we need to pay attention to making sure that the chemistry of the top layer of alloy welding, that will be exposed directly to...

DMW cracking is another fabrication issue that can and does result in equipment failure. It usually occurs at the weld juncture where carbon steel or low alloy steels are welded to austenitic (300 series) stainless steels in high temperature...

Cracks along the toe of a weld are not uncommon during fabrication, and can occur for a wide variety of reasons involving the metallurgy and process control of the the same issues covered above on repair welds can apply to repair welds on...

Liquid Metal Cracking (LMC) (aka "liquid metal embrittlement") is another insidious form of cracking that strikes when you least expect it. It most commonly afflicts austenitic stainless steels, but can afflict other copper, nickel and aluminum...

Carbonate cracking (CC) of carbon steel has seen an increase recently in frequency and severity in some refinery cat crackers, especially in fractionator and gas processing overheads. Some gas scrubbing units are also susceptible. CC is a form of...

Thermal shock is another one of those pressure equipment afflictions where communication with operating groups is a vital factor in prevention. Thermal shock failures usually involve sudden quenching of high temperature equipment and furnace tubes...

Cavitation is the sudden formation and immediate collapse of vapor or air bubbles in a liquid stream when system pressure falls below the vapor pressure of the liquid. The sudden collapse of these tiny bubbles generates enormous, though tiny forces...

This is the name given to a form of embrittlement that occurs in 400 series of stainless steels, duplex SS's and less commonly in some 300 series stainless steels containing a metallurgical phase called ferrite. The embrittlement occurs from 600...

This failure mechanism is unfortunately all too common in our industry. It's also known as stress rupture, and it is usually entirely preventable by proper maintenance and operating procedures. It occurs when equipment, piping or furnace tubes...

Now you say, he's got to be putting me on. What is green rot? I didn't invent it. I first read about it in one of the early texts on corrosion engineering by Ughlig or Fontana, the venerable corrosion professors at MIT & Ohio State. But when I...

I already mentioned this common affliction in the introduction. Caustic cracking was long called caustic embrittlement, but since no embrittlement actually occurs that name is fading away.

Welcome to a new series of articles about the ninety-nine leading types of degradation, flaws and failure that can and do happen to pressure equipment in the hydrocarbon process industry.

Petroleum coke production is an important source of revenue for many refineries. While coking units were initially constructed to deal with a waste product, these units are now of significant economic value.

Nelson Curve changes in the late 1980's provided cause for Shell Oil Company to look at more reliable NDE non-destructive evaluation methods for assessment of materials/equipment in high temperature hydrogen service. The primary change motivating...