A Selection of Consultancies by CMC Ltd,
representing the Company's wide Expertise
Range of problems addressed:
Problems ranged from high temperature corrosion problems in waste incinerators and car engines to water
treatment plants involving microbial corrosion. Corrosion in the construction industry included preparing a
feasibility study for a bridge in Bangladesh under adverse conditions, estimating the life of buildings and
recommending repair options for corrosion of reinforcements and corrosion of prestressed reinforced concrete
pipes. Marine corrosion was also addressed, for ships and other structures exposed to marine atmospheres.
Corrosion in the chemical industry required setting up a monitoring strategy and treatment of heat exchanger
Failure analysis for the oil industry was also carried out to determine stress corrosion cracking and hydrogen
Other consultancies involved materials properties and analytical techniques.
The above are some of the examples of problems addressed. They demonstrate the diverse nature of
consultancies conducted and the requirement of a multidisciplinary approach.
Microbiologically induced corrosion of a water treatment plant - Major consulting task
This was an extensive project which was thoroughly investigated technically, with possible litigation
consequences. Pitting of 316L stainless steel pipes and welds had been observed in the plant which had been
refurbished. The work involved examining the procedures employed, from feasibility study to plant
commissioning. The result of the investigation indicated that microbial infestation had occurred during the re-
commissioning stage. The project was multidisciplinary in nature and apart from taking a leading role in the
consultation, CMC was responsible for setting up a team to look at the various aspects (microbiology, chemistry,
chemical engineering and materials). Aspects of the work included a literature survey of the properties of
materials, microbiological analysis, failure investigation and examination of pitting characteristics, materials
examination involving microscopy and SEM, as well as various analytical techniques. Various scenarios for
dealing with the plant were put forward based on risk analysis.
Estimation of the life expectancy of a modified galvanised steel:
The project involved examining the thickness and microstructure of the coating and underlying steel and
estimating the coastal life expectancy based on environmental conditions with the aid of literature data.
This project examined the effect of a wax inhibitor on the efficacy of preventing crevice corrosion.
Modifications of inhibitor consistency and surface tension properties were put forward to improve its
performance using a spray technique. CMC was responsible for setting up the experimental programme and
interpreting the results, together with suggestions for improvement.
Cathodic Protection of high strength prestressing-steel wires:
This consultancy followed from a previous research project on the susceptibility of prestressing steel wires to
hydrogen embrittlement under various conditions. The consultancy project was to advise on the causes of
corrosion of wires in prestressed concrete pipes, the effect of wire composition and its performance and the
most suitable cathodic protection method for preventing corrosion and mitigating against hydrogen embrittlement.
Corrosion allowance and design of a bridge in flowing silt and water conditions:
This feasibility study involved a comprehensive analysis of the factors to be considered using two different
design considerations for a bridge in Bangladesh. The first design relied on high strength piles driven to great
depths to resist moving silt conditions. A corrosion allowance needed to be built into the steel and this had to be
calculated based on literature data and projected conditions. The second design related to reinforced concrete
piles and the types of concrete to be used as well as its thickness. Methods of protection against corrosion of
reinforcements were investigated.
Pitting Corrosion of cupro-nickel pipes in a heat exchanger and control methods:
This study involved an analysis of the factors that could lead to pitting of this material. It was found that
residues in the plant contributed to the initiation mechanism by depositing on the walls and setting up an oxygen
differentiation cell. Further work discovered discrepancies in the performance depending on the location and
how far this was from the injection point for acid cleaning. A programme for eliminating the causes of corrosion
was put forward, involving oxygen scavengers, monitoring, and frequent acid cleaning of the pipes with increased
Erosion Corrosion of an elbow of a well riser:
Advice was sought as to the appropriate method for increasing the life expectancy of the elbow joint which was
expensive. The introduction of an internal sacrificial section with erosion resistant properties, as suggested by
CMC, resulted in substantial savings for the company.
High Temperature Corrosion
Corrosion in a waste incinerator - Major Court Case
This was an extensive and high-profile arbitration case where a waste incinerator corrosion rate was in question.
The work involved taking samples from the incinerator and carrying out various analytical techniques e.g. X-ray,
SEM, AA. An extensive literature survey was also performed. A mechanism for the corrosion of the waste
incinerator was put forward based on the evidence collected and the operating temperature was then estimated
based on the analytical results and on the proposed corrosion mechanism. Our case was successful.
Corrosion of Engines by fuel additives: - Major court case
This case involved estimating the quantities of aggressive species from various sources and establishing a
mechanism of corrosion at the operating temperatures. Road de-icing salt intake was a significant factor and
evaluation of engine corrosion in various countries was considered. CMC was also involved in coordinating the
reports of other experts from different disciplines. Our case was successful.
Wire Explosion plasma coatings:
Molybdenum plasma coatings for the interior of metal cylinders have been deposited by a wire explosion
technique. The coatings are very adherent and wear resistant.
Modelling the release and migration of gases from a hot refractory oxide and its stress corrosion cracking effects -
- Major consulting task
The work involved thermodynamic and kinetic calculations to calculate the quantities of gases emitted and a
model to describe their migration through the oxide to the surrounding metal. Current models of stress corrosion
cracking were critically examined and modifications included to take into effect the chemical as well as the
physical aspects of stress corrosion cracking. Equations were developed to include the effect of various heating
rates of the oxide and consequent gas releases and stresses.
Courses for people working in industry
Many courses have been formulated by CMC and are currently available for people working in industry. The
courses are approved by the Institute of Materials, Institute of Corrosion and Institute of Marine Engineers.
Companies abroad have also asked for course formulations to suit their industries and which deal with corrosion
and management issues. CMC can produce any course to suit requirements - please enquire. Click here.
Corrosion Microscope: CMC has have developed a scanning reference electrode apparatus for the mapping
of localised corrosion and coatings deterioration, available through CMC Ltd. Please click here.