London Branch AGM

London Branch AGM

The branch AGM was held in March, which was followed by the “President’s talk”. The chairman, Paul Brook, reviewed the activities of the branch over the past year and noted that we had had excellent presentations. The Treasurer, Jim Glynn, announced that again our finances were in good shape, and that surplus monies will be returned to head office.  Paul then asked if any members wanted to join the committee, and confirmed that existing members were happy to serve for another year.   Paul also informed the meeting that the branch is close to completing a venue move from Imperial College, Kensington to the IMechE offices in Bird Cage Walk, Westminster.  This should be a great home for London branch future technical talks, which will restart following the summer recess in October, on the second Thursday of the month as usual. More details will be available on Institute web site in due course.

Gareth Hinds then presented his views on  the future of the Institute, and discussed ways we could adapt to changes, including environmental challenges, the rise of digital communications, and how to encourage more young engineers to join the Institute, and how to support them. This generated a lot of discussion and interesting suggestions.

The April meeting, the last of this season, was joint with The Welding Institute, and was given by Alan Denney of TWI, on the subject of “High tensile steel bolts and nuts: hydrogen embrittlement and failure in corrosive environments.’

Alan started by talking about the failure of threaded components used as shear connectors for earthquake resistance on the San Francisco Oakland Bay Bridge, which has been well documented in the technical press in the USA. These galvanised rods (in ASTM A354 grade BD steel) were pre-installed in 2008 in the supporting piers to the bridge superstructure which are above the water level. The superstructure was assembled and in 2013 the rod connectors were pre-tensioned hydraulically to 70% of UTS. A number of these suffered brittle failure, the published cause of which was that the rods failed due to hydrogen embrittlement arising from stress corrosion cracking.

Alan then proceeded to explain the conditions required for stress corrosion cracking, namely a combination of a susceptible material, a source of the hydrogen,  and tensile strength above a threshold value. He explained that the hydrogen could be either from internal sources in manufacture, or from an external source. The potential sources in manufacturing include hydrogen retained from steelmaking or hydrogen resulting from pickling of the components prior to coating. The external source would result from corrosion, the hydrogen being generated by the cathodic reaction. He explained that failures can occur in nuts as well as the bolts or threaded rods, and that in galvanized components
the zinc acts as a barrier to the outward diffusion of any trapped hydrogen.

Failures of structural bolts have a long history. Alan mentioned that his first encounter with bolts failing from hydrogen embrittlement was in the 1970s on a television transmission tower, with failures occurring in V grade and Y grade bolts on cold nights; the bolts being found on the ground in the morning, and his most recent experience of a failure was a few weeks before this talk. Apart from in transmission towers, such failures have also occurred in the recent past on prestigious building structures, and in offshore wind turbine towers. Recent occurrences known to Alan have been in large diameter high tensile bolts, generally in bolt grades 10.9 and above. He explained that there was a relationship with hardness of the fasteners (both bolt and nut), and covered recommendations in standards such as those published by DNV-GL for offshore wind turbine structures, which limit the highest strength grade to 10.9. He discussed the typical crack morphologies associated with hydrogen embrittlement and how the fracture surface could be ‘read’.

Alan then discussed some of the metallurgical aspects in bolt and nut materials and the recommendations and findings of work carried out by the Deutscher Schraubenverband (DSV) in relation to the desirable elements in the composition, and their proposed limits on chemical composition. He presented some findings from DSV on the failure thresholds in 10.9 bolts under ASTM F1624 test conditions with different coating types and then finished by summarising the findings:

n There is a risk of stress corrosion cracking with the use of fasteners with a UTS > 1000 N/mm2 in a corrosive or marine environment.

n The much-quoted guideline of 380 Hv as the threshold for stress corrosion cracking is not conservative, notably when there is a risk of external corrosion, even during temporary conditions.

n Controls which will improve their performance in marginal situations can be put in place for the bolt materials, their heat treatment and metallurgical controls, their coating systems and application, and their quality control and testing requirements .

However the main means of avoidance of SCC is to control the environment.

There was a lively question and answer session, with interesting contributions from the audience and the meeting was closed with a vote of thanks and a presentation to
the speaker.

Offshore Energy and Telegraph Cables

Organised by SCI’s London Group and the Institute of Corrosion – London Branch
The Evening Chair will be John T O’Shea, Hon ICorr Life Fellow

Thursday 26 September 2019, 17:30 for 18:00
SCI, 14/15 Belgrave Square, London, SW1X 8PS, UK

Book today! Free registration
E: conferences@soci.org
T: +44 (0)20 7598 1561
https://www.soci.org/events/offshore-energy-and-telecommunication-cables

This evening event includes two presentations, followed by a networking reception at 19:30. Attendance to this
event is free of charge, however places are limited. Please register today by visiting: http://bit.ly/Offshore_Energy
The event is open to SCI, ICorr, IOM3, LMS, and TWI members and guests.

Please click link below for details of the event:

Offshore Energy and Telegraph Cables – flyer

London Branch

London Branch

The February talk was by Dr Bijan Kermani of KeyTech, on corrosion, the outlook, challenges and future of the discipline, particularly in regards to hydrocarbon production. Having briefly touched on the economics of corrosion in the oil and gas industry, Bijan went on to present an overview of the projected global energy mix over the next two to three decades, highlighting that there is an increasing global energy demand and that hydrocarbons will contribute the majority of this. He emphasised that technology continues to play a fundamental role for the hydrocarbon industry sector’s business success, reducing capital and operational expenditure, environmental, safety and reputational risk, and increasing reliability. He emphasised that innovative materials, corrosion and integrity management technologies play a significant role in supporting this. He argued that while significant progress has been made over the years in understanding the root causes of integrity management threats with advances in technology and expertise, there still remains major challenges.

The talk covered three themes including (i) a technology outlook in energy, (ii) corrosion and materials challenges facing hydrocarbon production industry sector, and finally (iii) what is required to move the corrosion and metallurgy discipline forward. In this, a brief reference was made to the corrosion discipline with respect to future priorities to attract a new generation of high calibre professionals. It was said that our contributions to all aspects of social, environmental, safety and security are clear and that the discipline has had significant achievements. The key achievement is the provision of public welfare; a ‘positive image’ rather than the reduction of failures which may convey a negative image of our discipline. By this change of focus we can attract even a better generation of young students.

Bijan concluded that the future is bright, although many challenges remain and there is a growing requirement for innovative solutions with timely implementation to achieve next level performance.

London Branch News

London Branch News

The January talk by Dr Patricia Conder, Sonomatic Ltd, was on “Pipework Corrosion: Prediction and Reality”, and how differences in the spatial pattern of internal pipework corrosion, be it patchy or more uniform, impacts on the effectiveness of inspection, and how this can be used to improve understanding of the underlying corrosion behaviour. Patricia discussed how extensive corrosion is easy to find and measure, but in instances where wall loss occurs more randomly, the challenges of matching inspection strategy to the corrosion coverage increase. She discussed how thinking of inspection of as a statistical sampling process helps both inspection strategy and analysis. The audience were challenged to spot the difference between a corroding and non-corroding circuit 
within a second. This was successfully achieved by 
means of a graphical overview of the whole circuit inspection history.

This overview presented a route to mine into the data, to examine “groupings” based on corrosion mechanisms, for example testing to see if the bends really are corroding faster than the straights. She also discussed the use of integrity driven corrosion rates, based on how the overall wall loss of the circuit is changing, rather than focussing on per inspection location corrosion rates, which can exaggerate measurement variability. Although historically inspection has been based on manual ultrasonic thickness measurements and radiography, these techniques have only covered relatively small areas overall. Developments for pipework inspection offer everything from screening to more detailed high accuracy mapping. The challenges being to incorporate all these results into a database in a meaningful way to get added value from a change in inspection approach. Patricia finished the talk by reminding us to think corrosion: think spatial.

Pipework Corrosion- Prediction and Reality

Dr Patrica Conder receiving a token of appreciation from Trevor Osborne, together with Paul Barnes, branch chairman

The January talk of ICorr London branch by Dr Patricia Conder, Sonomatic Ltd, was on “Pipework Corrosion : Prediction and Reality”, and how differences in the spatial pattern of internal pipework corrosion, be it patchy or more uniform, impacts on the effectiveness of inspection, and how this can be used to improve understanding of the underlying corrosion behaviour.

Patricia, discussed how extensive corrosion is easy to find and measure but, in instances where wall loss occurs more randomly, the challenges of matching inspection strategy to the corrosion coverage increase. She discussed how thinking of inspection of as a statistical sampling process helps both inspection strategy and analysis. The audience were challenged to spot the difference between a corroding and non-corroding circuit within a second. This was successfully achieved by means of a graphical overview of the whole circuit inspection history.

This overview presents a route to mine into the data, to examine “groupings” based on corrosion mechanisms, for example testing to see if the bends really are corroding faster than the straights. She also discussed the use of integrity driven corrosion rates, based on how the overall wall loss of the circuit is changing, rather than focusing on per inspection location corrosion rates, which can exaggerate measurement variability. Although historically inspection has been based on manual ultrasonic thickness measurements and radiography, these techniques have only covered relatively small areas overall. Developments for pipework inspection offer everything from screening to more detailed high accuracy mapping. The challenges being to incorporate all these results into a database in a meaningful way to get added value from a change in inspection approach. Patricia finished the talk by reminding us to think corrosion: think spatial.

London Branch News

London Branch News

At the October meeting, Paolo Marcassoli from Cescor gave a very interesting talk on the use of Finite Element Method (FEM) in Cathodic Protection Design. Paolo introduced the advantages of FEM modelling, explained its mathematical principles and presented case studies where the technique had been implemented.

Paolo Marcassoli.

Paolo Marcassoli.

Over the past few years the use of computer aided approaches have improved the design of galvanic and impressed current cathodic protection systems. To ensure that protection conditions are achieved at each point of the structure, correct anode spacing is critical. FEM allows accurate analysis of structures with complex geometries, and the impact of various factors on corrosion control, providing precise prediction of protection current distribution.

FEM is a numerical technique for solving boundary value problems, it minimalizes an error function, generating a stable solution. It solves simple equations over small subdomains, i.e. finite elements, to approximate more complex equations over a larger domain. Such analysis considers both, the primary current distribution related to electrolyte resistivity and the secondary current distribution related to electrode reactions. Boundary conditions are characterized by electrochemical behaviour of the metallic surface under protection, for example through the Tafel equations. The electrical field is then solved using Laplace equation.

The first case study demonstrated the application of FEM on an above ground crude oil storage tank, where the bottom of the tank was protected internally by coating and galvanic anodes, flush-mounted type or zinc ribbon, depending on the water hold-up. This case is described in more detail in the article on page 14. In the second case study Paolo presented how FEM benefits retrofit CP design of offshore assets. This included applications in: offshore platform protected by galvanic anodes, offshore platform retrofitted by impressed current system, subsea pipeline retrofitted by galvanic anode sleds, and Single Point Mooring retrofitted by galvanic anodes clamp and pods. The study showed that FEM modelling in cathodic protection design is a very useful tool that helps to ensure thorough protection of the asset and 
possible reduction of costs by optimization of anodic system installation, and determining need for a new retrofit system.

This was an excellent talk and was well received by the audience. The technique presented is currently widely used in the industry and is recognized by professional organisations. It surely is a step forward 
in cathodic protection design and will continue to develop in the future.

The November meeting was devoted to the presentations from the Young Engineers on the results of their YEP case study of a heat exchanger failure. This was the culmination of 12 months of study by the delegates who have worked through modules that span the breadth and depth of the technologies used in our industry.

The YEP delegates and mentors.

The YEP delegates and mentors.

It was a truly fantastic evening with 3 excellent presentations from the teams
Team Boran:
Agnieszka Knyter
Rachel Colpitts
Liam Fox
Konstantinos Katsounis
Team Doggett:
Daniel Burke
Oliver Smith
Caroline Earl
Jessica Easton
Team Googan:
Mark Fearns
Stephen Shapcott
Liya Guo

There was a good deal of questions from the audience after each presentation and following which the judges retired to deliberate. Bill Hedges from BP, on presenting the award, said how hard it had been to select a winner as they were all so good. However there has to be a winning team and that was Team Doggett, who will be travelling to the USA in April 2019 to attend the NACE Conference in Nashville, where a whole programme of events will be arranged. They will post a blog of their activity and learnings on a daily basis on the Institute website. The organisers are grateful to the President and staff of NACE for pledging their support to the winners whilst they are in Nashville by providing free conference registrations, and access to the student award ceremony.

The winning team will also present their conference learnings during the London branch 2019 winter series lectures.

The response from the delegates attending this programme has been incredibly encouraging;
“This programme has altered the way I think about my work and how I carry it out”
“I have found a new job and moved to London living in Kew Gardens and cycling to work each day. I love it”
“I hadn’t realised the value of ICorr and I will go back to work on Monday and encourage them to engage”
A comment from one of the senior engineers in our fraternity gave the programme even more credibility, “This is probably the most important function in the UK Corrosion calendar, it’s truly fantastic”
It’s also interesting to note that Agnieszka of Team Boran, travelled from Poland in 2015, under her own steam, to hear the previous YEP case study presentations, and decided then she wanted to be involved in the next YEP programme.
Thanks go to all those involved in the process; the organising committee, the lecturers, the hosts, the mentors, the judges, the delegates, and if course a big thank you to the sponsors of the event, BP.

The winning team and mentor, Rob Doggett with Bill Hedges.

The winning team and mentor, Rob Doggett with Bill Hedges.

The second joint meeting of the branch with the SCI London Group was held on 25 October, at their prestigious headquarters in Belgrave Square. This ultra-modern auditorium made for a most comfortable setting and was enjoyed by an attendance of over 60.

The evening chairman, John T O’Shea, a Past President of ICorr, began the procedures by thanking Dr Fred Parrett, currently Hon. Treasurer of the SCI London Section, for all his work in helping to organise this event.

John O’Shea introducing the evening.

John O’Shea introducing the evening.

The first presentation “A Fighting Ship” was based around the Mary-Rose project at Portsmouth. This was given by Professor Eleanor Schofield, Head of Conservation and Collections Care at the Mary Rose Trust. Eleanor graduated from Imperial College, where she also received her PhD in Material Science. She has recently received an Honorary Chair at the University of Kent, at Canterbury.

Professor Schofield began her talk by correcting the too often quoted story that the Mary Rose sank in 1545 on her maiden voyage. In fact she was built in 1510 and served for 34 years as the flagship of Henry VIII’s navy in many battles, particularly in wars against France. Following the lifting of the ship out of the seabed mud, the timber hull was treated over many years by spraying with water and polyethylene glycol to prevent further deterioration once it was exposed to the air.

Perhaps less well known is the work in restoring and maintaining over 19,000 artefacts that had also been recovered. A significant part of the collection was the 1200 + iron cannonballs, which had been exposed to sea-water since the ship sank, and which were in danger of corrosion when exposed to the air due to the chloride in sea-water. It was vital that ways were found of preserving the these, as it was recognised that while the cannons were made to last and be used many times, the cannonballs were only needed for a one-off use, and thus greatly inferior in their quality and standard of manufacture.

Professor Eleanor Schofield.

Professor Eleanor Schofield.

Initially researchers attempted to remove chloride from the cannonballs, by soaking in water with and without chemical treatment. Chloride reduction by heating in an atmosphere of hydrogen was also attempted, but unfortunately these methods did not successfully prevent disintegration when they were later put on display. To better understand this problem, Professor Schofield, established a joint research project with the department of archaeology at UCL and the UK Diamond Light Source in Didcot which is the UK’s national synchrotron. This works like a giant microscope, harnessing the power of electrons to produce penetrating bright light X-rays, which combined with absorption spectroscopy, and fluorescence mapping, made it possible to visualise the differences in the corrosion profiles. These could be traced to the treatments applied in the 35 years since the cannon balls were recovered with the Mary Rose. The results revealed detailed maps of the elements involved in the corrosive process, giving an unprecedented insight into conservation on a molecular scale. This crucial information will help to protect these and other cultural heritage artefacts for many decades to come.

The second presentation, “Fighting Corrosion” was given by Jim Glynn, a previous chairman of London Branch. Jim concentrated on the “dynamic duo” of corrosion protection – a suitable protective coating as the primary source of defence, supported where appropriate by a cathodic protection system to prevent any corrosion occurring at areas of coating damage.

It is often commonly believed that rusting is a simple, chemical oxidation reaction – but it is not. Aqueous corrosion is a complex, multi-stage step process which includes electron transfer at the molecular level. Thus these electro-chemical reactions during corrosion can be influenced by the external application of electrical potentials. Under the right circumstances, corrosion can be stopped by applying the appropriate level of negative potential using a DC current supply.

Jim presented many examples where the correct conditions of a good coating and a suitable working cathodic potential were present. However, he also described many examples where this was unsuccessful. These included a pipeline coating that had totally disbonded and broken away from the pipeline, due to a higher potential than required being applied, which generated hydrogen gas on the surface of the pipeline, causing the coating damage.

He also described Thermally Sprayed Aluminium (TSA) applications, which are excellent protective coatings when properly applied. The aluminium content can act as its own in-built cathodic protection anode. However, in the wrong environment, the aluminium can be quickly used up, and premature failure occurs.

Jim Glynn.

Jim Glynn.

Jim expanded his presentation to compare recent case studies of retro-fitting remote anode beds to two similar North Sea platforms which had exceeded their design life, but it was decided that the protection of these structures subsea could be extended using additional cathodic protection. One had been fully coated with coal tar epoxy, while the legs on the other had been left bare, but with a built-in corrosion factor that should have exceeded its expected life. The coated structure required a current output of 1,000 Amps, while the bare steel legs needed around 7,500 Amps, to produce the correct negative potentials, with these high DC currents supplied by banks of adjustable transformer rectifiers located on the platform decks.

Jim also interspersed a number of quiz questions, asking the audience to identify some notable “Dynamic Duos” in life, film and comic books, which was well received and considered a fun way to conclude the presentations.

The vote of thanks was given by Dr Parrett and he presented the speakers with ICorr engraved pens, as a memento of the evening, which was followed by refreshments and networking in the Garden Rooms.