Testimonials: BAE - Nuclear Submarine

Zwick Roell Indentec assists in controlling build quality of world beating nuclear submarine

Picture of a submarine at night BAE logo and photo of a submarine at night

"Indentec demonstrated the highest level of technical competence during the negotiation..."

She is 97 metres long and weighs 7,400 tonnes. The vessel has a sonar system with the processing power of 2,000 laptop computers which is so sensitive it can hear other vessels 3,000 miles away and can carry a payload of 38 Tomahawk cruise missiles capable of hitting targets 1,200 miles away. She is clad in high-density rubber tiles and noise and vibration suppression techniques are used to maintain the submarine's stealth.

HMS Astute, one of the Royal Navy's newest nuclear submarines, is one of the most sophisticated and powerful vessels ever built and able to travel over 500 miles in a day, allowing deployment anywhere in the world within two weeks. The nuclear reactor, which drives the propulsion system, will last the 30 year life of the vessel without needing to be replaced.

Picture of a submarine in the daytime

Meticulous and painstakingly detailed examination of every aspect of the build process was required to ensure every component, system and module was checked and proven, in line with the exacting standards demanded by both BAE Systems and the Ministry of Defence customer.

As part of the quality drive, Mike Wilson, Consultant Metallurgist in the Materials Technology Centre at BAE Systems Maritime Submarines, was tasked with providing a metallurgical assessment of double sided, full penetration welds. The challenge was to provide more comprehensive data and to save time in the hardness testing procedure compared with existing methods. Mike turned to Zwick Roell Indentec to assist him identify the optimum solution.

Indentec was selected as the supplier of a sophisticated Vickers hardness testing system which incorporates automatic indentation, motorised XYZ stage, multiple lenses and sample scanning software. The installed system also utilises sophisticated software to facilitate stitching of multiple images, accommodating the microscopic assessments of complete welds, heat affected zones and parent metal. The machine test specimen stage is capable of achieving indentation spacing of just 250 μm in conjunction with a 1kgf hardness force producing arrays of over 6,000 hardness points.

Mike Wilson commented that, "Indentec demonstrated the highest level of technical competence during the negotiation to procure the best solution and was the only company capable of providing an XYZ stage with the required accuracy of positioning and extent of travel."

ZHV30-A Hardness Tester

Zwick Roell Indentec ZHV30 hardness tester

With the installation of this system Principal Metallurgist's Andrew Bell and Stuart Hambling were able to migrate from basic Q.A. procedures and develop comprehensive wide field hardness surveys. Using some manipulation of commercially available software they are able to produce a visual map of hardness values from acquired data, to enable accurate assessment of hardness and weld strength across large welded sections.

"The installation of the fully automated Indentec system has enhanced the technical capability of the laboratory beyond anything we thought possible with respect to full hardness surveys on welded sections," said Mike.

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Hardness map 1 Hardness map 2

Typical hardness survey maps