Microstructures of high strength steel welding consumables from directed thermal cycles by shaped laser pulses

Document identifier: oai:DiVA.org:ltu-76032
Access full text here:10.1007/s00170-020-05749-1
Keyword: Engineering and Technology, Materials Engineering, Manufacturing, Surface and Joining Technology, Teknik och teknologier, Materialteknik, Bearbetnings-, yt- och fogningsteknik, Filler wire, Consumable, Welding, Thermal cycle, Microstructure, Cooling rate, Produktionsutveckling, Manufacturing Systems Engineering
Publication year: 2020
Relevant Sustainable Development Goals (SDGs):
SDG 9 Industry, innovation and infrastructure
The SDG label(s) above have been assigned by OSDG.ai

Abstract:

Filler wire metallurgy was modified through temporally shaped laser pulses, controlling cooling cycles in a recently developed method. Trends were identified through efficient mapping while maintaining representative thermal cycles of welding processes. A primary pulse melted preplaced filler wires while a secondary, linearly ramped-down pulse elevated the nugget to re-austenization temperatures. Ramped-down pulses resulted in linear cooling rates comparable with and exceeding furnace-based methods, between 50 and 300∘C/s. The linear decay of laser output power guided the temperature through a regime to obtain desired microstructures. For three very high-strength steel filler wire chemistries, quenching resulted in smaller plates with cross-hatched microstructures, accompanied by grain boundary ferrite. Finer bainite microstructures started forming for fast linear temperature decay, about 250∘C/s. Slower decay or a weaker third cycle formed coarser microstructures with coalescent sheaves and less cross-hatching.

Authors

Stephanie Robertson

Luleå tekniska universitet; Produkt- och produktionsutveckling
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Jan Frostevarg

Luleå tekniska universitet; Produkt- och produktionsutveckling
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Anandkumar Ramasamy

Lincoln Electric Europe, Nijmegen, Netherlands
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Bert Kalfsbeek

Lincoln Electric Europe, Nijmegen, Netherlands
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Jörg Volpp

Luleå tekniska universitet; Produkt- och produktionsutveckling
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Alexander F.H Kaplan

Luleå tekniska universitet; Produkt- och produktionsutveckling
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