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Welding Metallurgy and Weldability

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An understanding of the properties of the makeup of alloys and the effects of joining methods on their microstructures is crucial to ensure the performance of components and structures in service.

TWI has a broad mix of engineers and consultants with up-to-date expertise, industry experience and strong academic backgrounds, allowing us to bridge the gap between academia and industry and provide world-leading consultancy services on metallic materials.

Our multi-disciplinary teams can provide advice on:

  • Alloy selection
  • Diagnosis of failure mechanisms
  • Fitness-for-service
  • Development of specialised joining techniques and optimisation of existing ones
  • Assessment of microstructures
  • Testing of interactions with extreme environments.

Our expertise covers ferrous alloys (steel), aluminium, titanium and corrosion-resistant alloys.

A fundamental aspect of a metal’s property is its weldability: its ability to be welded and suitability for different welding techniques. This is not a fixed parameter for a given material, but will depend on joint details, service requirements and available welding processes and facilities.

A metal’s weldability is a measure of how easy it is to:

  • Obtain crack-free welds 
  • Achieve adequate mechanical properties
  • Produce welds that are resistant to service degradation.

The process of welding can have a significant effect on a metal’s properties; many of the characteristics of welded joints are determined by the microstructures developed during welding.

TWI is dedicated to the evaluation and understanding of the relationships between material properties and their underlying structures, with particular focus on the effect of joining on the microstructures developed.

The thermal cycles imposed during welding can completely change the microstructure of the parent material, posing serious challenges for material scientists looking for the optimal joining technique. The rapid solidification of the weld metal itself, composed of a mixture of parent materials and filler material (when filler material is used) adds to the challenge.

We have a team of specialists covering metallurgy, joining techniques, non-destructive testing, structural integrity and modelling who, together, form a powerful resource to solve all kinds of joining challenges for a wide range of functional materials.

TWI has introduced numerous inventions and innovations in this field, and we continue to invest in improvements to our capability and understanding of joining technologies.

For more information please email: