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Life Cycle Assessment (LCA) is applied in evaluating environmental impacts of state-of-the-art welding technologies. Manual Metal Arc Welding (MMAW), Laser Arc-Hybrid Welding (LAHW) and two Gas Metal Arc Welding (GMAW) variants are used to join a plate of 20 mm thick structural steel. The LCA results indicate that for 1 m weld seam, MMAW causes the highest environmental impacts in global warming potential (GWP), eutrophication potential (EP), acidification potential (AP), and photochemical ozone creation potential (POCP) among the selected processes, and the LAHW variant performances the least. Filler material and electricity consumptions generally dominate the impacts and reach shares of up to 80% and 61% in the respective impact categories. However, electrode coating consumption in MMAW remarkably contributes impacts on AP and EP, for instance 52% of AP and 76% of EP. Strategies for improvement of the applied welding technologies are discussed.
Welding is the most important joining technology. In the steel construction
industry, e.g. production of windmill sections, welding accounts for a
main part of the manufacturing costs and resource consumption. Moreover, social
issues attached to welding involve working in dangerous environments. This aspect
has unfortunately been neglected so far, in light of a predominant focus on economics
combined with a lack of suitable assessment methods. In this chapter,
exemplary welding processes are presented that reduce the environmental and
social impacts of thick metal plate welding. Social and environmental Life Cycle
Assessments for a thick metal plate joint are conducted for the purpose of
expressing and analysing the social and environmental impacts of welding.
Furthermore, it is shown that state-of-the-art technologies like Gas Metal Arc
Welding with modified spray arcs and Laser Arc-Hybrid Welding serve to increase
social and environmental performance in contrast to common technologies, and
therefore offer great potential for sustainable manufacturing.
The results of a collaborative research project on laser beam weldability of carbon steels of high sheet thickness are presented. That includes single and multiple pass welding of 16 mm and 20 mm thick plates, as well as the investigation of acceptable tolerances i.e. gap bridgeability and edge misalignment. For the welding experiments fibre lasers with 8 kW, 20 kW laser power and different GMAW-techniques were used in various applications. With the 20 kW fibre laser 16 mm plates could be welded with a single pass, 20 mm required a seam preparation or alternatively preheating of the material. For multi pass welding with 8 kW laser power a joint preparation with a single V-butt joint with a broad root face (Y-groove) was applied. The root pass was always welded with a hybrid process, the filler passes with a hybrid process as well as a GMAW process which produced the best results.