Safety of Joined Components

The core competence of Division V.5 lies in the field of safety and reliability of joined components and assemblies during fabrication and service. In this respect, evaluation of the interaction between material, process and structure plays a crucial role. The central issue is clarification of the hot and cold cracking phenomenology. Apart from investigations into cracking resistance, new high-performance joining techniques such as laser and laser hybrid welding are qualified and, in addition, new alloy concepts for welding filler materials are developed for high quality joining of innovative materials. Safety and reliability assessment of joined components is carried out not only by using laboratory specimens, but above all by performing component tests and full-scale tests. This is accomplished by adapting existing test procedures as well as enhancing new methods. The overall activity is assisted by application and development of respective simulation techniques.

Workscope of the Division

• Determination of the cracking resistance of joined components during fabrication and service; clarification of the hot and cold cracking phenomenology
• Determination of the influence of thermal joining on the joint properties and on component safety considering service load and corrosion exposure
• Evaluation of the complex interactions between material, welding process and structure
• Enhancement of test procedures
• Weldability investigations of steels and non-ferrous metals
• Qualification of modern high-performance joining techniques for thick-walled components; short-term metallurgy
• Investigations of spot weldability and of the joining parameter influence on the strength of resistance welded components, above all of those made from super high-strength steel grades
• Calculation of welding-specific temperature fields, distortions and stresses
• Development of new simulation methods

Equipment and investigation methods

• 16 MN large-scale testing facility (GAPSI)
• Hot and cold cracking testing (MVT, CTW, Tekken, etc.)
• Fusion and resistance welding equipment
• 20 kW-fibre laser
• 6 kW CO₂-laser
• 4.4 kW Nd:YAG-laser
• High-speed camera, thermo-camera
• Distortion measuring systems (ARAMIS, displacement transducer, strain gauge)
• Residual stress determination (mobile X-ray diffractometry, drill hole method)
• Determination of hydrogen in welds (hydrogen hot gas extraction, mercury method)
• Hard- and software for numerical simulation of welding

Expertise and contact persons

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