Wednesday 4 August 2010

Independent chemical analysis

Currently celebrating its 90th anniversary Keighley Laboratories is putting the spotlight on its advanced Chemical Analysis facility, bringing it to the attention of an even wider spectrum of industry. Its team of analytical chemists has over 150 years’ combined experience, ensuring that samples are assessed by the most economical and efficient method, depending on the type of material, the size and form of specimen, and the degree of accuracy required. It is a level of service that has retained customers for 30 or 40 years and attracted business from across Britain and as far afield as Saudia Arabia.

Chemical analysis at the laboratory involves determining the elemental constituents of a wide range of materials, including cast iron, steel and stainless steel, aluminium, copper, nickel and titanium alloys, weld metals and non-metallic compounds like foundry sand. The laboratory employs state-of-the-art spectroscopy equipment, classical gravimetric and volumetric ‘wet’ methods, and qualitative depth profile analysis to check that submitted samples meet a required specification, for quality assurance purposes, as well as identifying any material coatings and metallurgical treatments.

In addition to analysing known samples from general engineering companies, foundries, the aerospace industry, galvanisers and platers, importers and the like, Keighley Laboratories also applies reverse engineering principles to unknown components. This enables parts of existing machinery to be identified and replicated where documentation is lost, for example, mixed stock to be reclassified when certification is missing, or corroded parts to be replaced with like-for-like material. Similar examinations also form part of the company’s Problem & Failure Investigation service, for forensic analysis of failed components, health & safety investigations and insurance claims.

“It is relatively unusual for an independent metallurgical services company to offer this level of experience and equipment,” says Chief Chemist, John Whittaker. “We offer a prompt turnaround and a highly personal service and, because we don’t manufacture anything ourselves, there are no confidentiality or conflict-of-interest issues.”

Specimens typically arrive by rail or carrier and range in size from a minute speck of material to a solid component or sample of virtually any size, with pricing dependent on the complexity of analysis and the quantity of material. When dealing with solid pieces of metal, the laboratory’s Glow Discharge Spectrometer is the instrument of choice, since it offers the quickest, most accurate bulk analysis of steel, stainless steel, nickel, aluminium and copper alloys, as well as quantitative depth profiling.

Where the sample size is limited or the format unsuitable, an Inductively Coupled Plasma Spectrometer is employed, which uses an argon plasma and enables low sample weights to be analysed down to parts per million detection limits. It is a very sensitive technique for identification and quantification of elements in a sample, although this ‘wet’ process does take a little longer.

For the precise measurement of residual and trace elements, the Flame Atomic Absorption Spectrometer is the preferred analytical tool, measuring down to parts per million in a sample; this method is also useful where no certified reference materials are available. In addition, classical chemical analysis techniques are used to augment spectrometry instruments, to provide a ‘control’ check for results and determine gravimetric, volumetric and photometric characteristics.

Results usually take the form of material certification, positive material identification or trace element analysis and are typically emailed to the client. Work is carried out to UKAS Metallurgical Laboratory Service accredited standards and conforms with relevant BS EN ISO specifications.
“Basically, if a sample can be delivered or posted to Keighley, we can accept commissions from anywhere in the world and analyse virtually any metal or metal-related material,” adds John Whittaker. “With manufacturers and suppliers working to ever tighter technical specifications and quality control high on the agenda in the engineering industry, it’s an independent service that is in growing demand.”

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