Failure Investigation
Corrosion and related failures of plant result in unplanned stoppages, lost production, repair costs and have possible safety implications for plant and personnel. Since the majority of plant is not monitored for corrosion or cracking, failures tend to be unexpected and largely unpredictable although periodic surveys can reduce the likelihood of failure. STL's Corrosion division offers a fully impartial investigation service to all industries, worldwide. Our senior staff and consultants have extensive experience of failure investigation work. We respond rapidly, diagnose the problem efficiently and provide recommendations for replacement or remedial action so that you, the customer, can get back into operation as quickly as possible.

Our staff travel worldwide to investigate failures on site. Site work involves collecting information relating to the failure, sampling the process fluids and environment, marking up areas for examination in the laboratory, and assessing the condition of the rest of the plant. Much progress can be made on site by experienced investigators, and at least a provisional diagnosis can usually be made. Samples removed on site are taken back to Sheffield for further work.

The outcome of a Sheffield Testing failure investigation is a comprehensive report giving the reasons for failure, with recommendations for control strategies to prevent further problems. In some cases litigation is the outcome, for which we prepare expert witness statements. Some failures are investigated on behalf of insurance companies.

We have a well-equipped modern laboratory with metallurgical facilities and micro-analysis in house. This is supplemented by electron microscopy and surface analysis where appropriate. Our own machine shop permits us to cut up large specimens and our test house conducts any mechanical testing appropriate to the investigation.

Typical failures include:

• general corrosion, localised corrosion and sulphide stress cracking of carbon and low alloy steels.
• pitting, crevice corrosion and chloride stress corrosion cracking of austenitic stainless steels.
  hydrogen embrittlement and environmental cracking of duplex stainless steels.
• crevice corrosion of nickel-base alloys in marine environments, and general corrosion in severe acidic conditions in the chemical process industry.
• pitting corrosion of aluminum alloys.
• stress corrosion cracking of copper alloys.
• All engineering materials are susceptible to corrosion and related degradation phenomena, from cast iron to titanium alloys.