"We approach welding from a holistic perspective, combining metallurgy, process, design and control"
We combine applied research, failure analysis, advanced simulation and technical guidance
Industrial welding is facing a crucial moment in which the pressure to ensure safer and more efficient joints coexists with the persistence of defects that continue to generate incidents in sectors, such as energy, transport, automotive or infrastructures. In this scenario, the TECNALIA’s contribution is vital, as we combine applied research, failure analysis, advanced simulation and specialised technical guidance to help companies understand and control increasingly demanding processes.
Our expertise in metallurgical characterisation, advanced testing and digitalisation of the welding process is crucial for industries seeking to reduce risks and improve the reliability of their joints.
Industrial welding faces a complex context
The industry is facing a context marked by a shortage of skilled welders, the incorporation of advanced materials and processes and the need to comply with strict regulations and specifications, such as EN ISO 3834, EN 15085, EN 1090, DNV, NORSOK, API, PETROFAC, ASME IX or AWS D1.1.
Added to this is the pressure for sustainability and energy efficiency, which requires lighter structures to be designed, components to be repaired rather than replaced and the service life of critical assets to be extended.
However, these advances are accompanied by problems that have been present for decades: porosity, lack of fusion, hot cracking, cold cracking, excessive distortions or residual stresses that compromise the integrity of the joints and generate high costs in terms of rework, plant shutdowns or in-service failures.
The growing challenge of dissimilar materials
One of the most complex challenges in recent years is the welding of dissimilar materials. The energy transition has increased the number of cases in which it is necessary to join carbon steels with stainless steels or stainless steels with copper alloys or even ceramic materials with components that have been repaired several times or even materials with incompatible heat treatments.
Metallurgical problems and material performance
- From a metallurgical point of view, hot cracking continues to be associated with low melting point segregations in the bead, especially in high strength alloys or in rigid geometries.
- The cold cracking is still linked to diffusible hydrogen, a problem that is particularly prevalent in high strength steels used in the automotive and energy sectors. The Heat Affected Zone (HAZ) remains a critical point: grain growth, tempering embrittlement or loss of toughness may compromise the integrity of the joint even when the bead appears correct in surface inspection.
- The residual stresses, which are often underestimated, continue to be responsible for deferred failures and distortions that lead to costly rework.
Process variability and appearance of defects
At the process level, variability remains the main enemy. Even on robotic lines, small changes in gas flow, stick-out, positioning, feed rate or surface cleanliness may lead to critical defects.
- Lack of penetration and the lack of fusion still occur in machined joints when the parameterisation does not match the actual material tolerances.
- Porosity continues to be associated with surface contamination, moisture in the thread or instability in the shielding gas.
- Distortion, especially in thin sheets and lightweight structures, is a growing problem in the electrical automotive sector, where weight reduction requires increasingly reduced thicknesses.
Organisational constraints, traceability and inspection
At the organisational level, the sector still suffers from structural problems.
- The shortage of qualified welders leads to subcontracting chains, which dilutes technical responsibility and hinders traceability. The lack of robust procedures (WPS/PQR) and the absence of full records of actual parameters remain frequent causes of non-conformities.
- Although non-destructive testing (NDT) is advanced, it still has its limitations: conventional ultrasound does not properly detect unfavourably oriented defects, radiography has safety and resolution restrictions and visual inspection remains extremely operator-dependent.
Digitalisation and advanced control of the welding process
In this context, digitalisation and Industry 4.0 are introducing tools that allow for more in-depth control of the process.
- The integrated sensor on torches and robots enables real-time recording of current, voltage, speed and flow rate, generating full traceability of the bead.
- Digital welding twins enable distortions, residual stresses and microstructures to be predicted before the part is manufactured.
- Artificial intelligence is starting to detect defects through machine vision and signal analysis, reducing subjectivity and increasing repeatability.
- Data integration into unified platforms enables actual parameters, consumables, WPS, inspections and NDT results to be linked, facilitating evidence-based decision-making.
Numerical simulation and advanced testing to prevent failures
Numerical simulation has become an essential tool to anticipate problems. Thermo-mechanical models optimise welding sequences, reduce distortions and assess the compatibility of dissimilar materials.
- In recent projects, simulation has enabled critical joints in energy structures to be redesigned, reducing residual stresses and avoiding subsequent repairs.
- Advanced non-destructive testing, such as TOFD, phased-array or active thermography, identifies defects that had previously gone undetected, while electron microscopy, toughness and fatigue testing provide an in-depth understanding of failure mechanisms.
TECNALIA helps move towards a safer and more efficient welding model
Yet again, TECNALIA's contribution is key. Our work in failure analysis, development of simulation models, research into consumables and processes and supporting companies in the digitalisation of welding enables the industry to move towards a safer and more efficient model.
As Mario Oyarbide, expert in welding engineering and industrial technical consultancy at TECNALIA explains, "in most of the incidents we investigate, the visible defect is only the symptom. The real cause often lies in the lack of process control, lack of data or interaction between advanced materials whose compatibility has not been appropriately assessed". His vision sums up the importance of approaching welding from a holistic perspective, combining metallurgy, process, design and control.
For further information, TECNALIA provides technical guidance on industrial welding, as well as welding coordination in strategic sectors.