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Roger King & Failure Control Metallurgists and Materials Scientists
R & D


Glass Ceramic Coatings for Wear and Corrosion Resistance

Emergency shut off valves for pipelines remain in the open position without operating for long periods of time. Because of this minute amounts of corrosion products can jam the moving parts which then fail to operate during an emergency. We performed a study to augment the high alloy steel with a lining of lithium oxide based glass ceramic with improved corrosion and erosion resistance. This was chosen for a matched coefficient of thermal expansion with the underlying steel, simple established application methods in the glass condition and excellent properties in the transformed (ceramic) state. We were also able to advise on sourcing, process control and testing to demonstrate the efficacy of this coating.

Spherical Elastomeric Bearings

This type of bearing uses concentric shells of rubber and steel, the steel between the rubber layers being highly stressed and subject to significant fatigue loading in the present application. Our client was the U.K. leader, but had no expertise in the metallic components for this novel design of bearing. Failure Control performed a turnkey contract for consultancy, material characterisation and testing, and fatigue analysis of steel components. Detailed manufacturing controls and QA/QC provisions for the interleaf spinning process were established since controlled strain hardening was essential to provide the required balance of properties. Lastly we developed process controls for recycling the metallic components if a bearing was defective and had to be scrapped.

Material Toughness Requirements for Welded Tubular Joints

The Department of Energy commissioned this study to develop better methods of assessing fracture toughness requirements in offshore "jacket' platforms than was provided by the (now superseded) British Standards document PD6493. Welded tubular joints present quite different analytical problems to stiffened plate construction and the more open provisions of the replacement document (BS7910) allowed many of our proposals to be implemented. Economic benefits included reduced requirements for post weld heat treatment and a greater flexibility in the choice of weld procedure and welding process.

Ceramic Windows for Moisture Measurement Equipment

Our client designs and manufactures a range of moisture measurement equipment for precise control of water content in mixed concrete using the principal of microwave absorption. An alumina disc was used to protect the transducer from the mix and was selected by the client for good wear resistance and transparency to microwaves. Breakages of the window indicated the need for a more compliant mounting of the transducer and a stronger tougher window. Failure Control helped re-design the window in stabilised zirconia with a new profile and modified seal arrangements to reduce stress concentrations. These changes have been entirely successful in preventing the re-occurrence of breakages and system performance is unimpaired.