H2WeldEng: Development of universal design concepts for weld seams under the influence of pressurized hydrogen for the time and cost-efficient dimensioning of hydrogen infrastructure components

Project description

To realize a sustainable energy system in the course of the energy transition, hydrogen is indispensable as an energy carrier. Green compressed hydrogen is particularly well suited for establishing a large-scale H2 infrastructure. However, when designing or retrofitting components that are in contact with hydrogen, its effects on materials must be taken into account, as these can lead to a drastic reduction in mechanical properties and to premature and sudden component failure (hydrogen embrittlement). This applies in particular to welded joints, which are used as connecting elements in almost all machine components and come into direct contact with hydrogen in nearly all components utilized within the hydrogen infrastructure.

Welded joints always represent limiting factors for component dimensioning due to their lower fatigue strength and service life compared to the base material as a result of residual stresses, coarse-grained structure, and geometric and metallurgical notches. This tendency is further exacerbated in a hydrogen atmosphere. When designing components for hydrogen infrastructure, it is therefore essential to consider the reduction in strength and service life of welded joints. If this is done — as is currently the case due to the lack of suitable design codes — on the basis of overly conservative reduction factors, the result is significantly higher sheet thickness than under conventional environmental conditions. This leads to long welding times (and thus long production times) as well as high demand for resources.

The aim of the H2WeldEng project is to develop and validate design concepts for welded joints in components of the hydrogen infrastructure that allow the influence of H2 to be adequately and practically taken into account in dimensioning and strength assessment. The methodology to be developed is designed to be applicable across industries and will be validated within the project for applications in the field of H2-compatible pipelines, hydrogen compressors, and peripheral components. The goals are to reduce conservative approaches in existing design guidelines, reduce sheet thickness and welding times, and accelerate the construction of new H2 infrastructures. The welding processes considered focus primarily on the widely used metal active gas (MAG), tungsten inert gas (TIG), and submerged arc welding (SAW), with laser welding and cladding welding included as complementary processes. The methodology developed in the project can be implemented directly in established codes and standards in the future. The project therefore makes a fundamental contribution to the standardization of design concepts for components of the hydrogen infrastructure.