Investigation of thermal influence on weld microstructure and mechanical properties in wire and arc additive manufacturing of steels

• DOI: 10.1016/j.msea.2022.143690
• Publication Date: 2022-08-09T05:52:54Z
• Authors: Suraj Panicker; Hari P.N. Nagarajan; Jari Tuominen; Madan Patnamsetty; Eric Coatanéa; Karl R. Haapala
• Keywords: Weldability; Acicular ferrite; Equiaxed crystals

Alloy steels are commonly used in many industrial and consumer products to take advantage of their strength, ductility, toughness properties. In addition, machinability weldability performance make alloy suitable for a range manufacturing operations. The advent additive technologies, such as wire arc (WAAM), has enabled welding into complex customized near net-shape products. However, the functional reliability as-built WAAM is often uncertain due lack understanding effects process parameters on material microstructure mechanical properties that develop during welding, primarily driven by thermal phenomena. This study investigated influence phenomena two (G4Si1, mild steel, AM70, high-strength, low-alloy steel). interrelationships between parameters, heating cooling cycles welded part, resultant were characterized. part experienced multiple reheating cycles, consequence layer-by-layer approach. Thus, high temperature gradients at start weld formed fine grain structure, while coarser grains height increases gradient decreased. Microstructural analysis identified presence acicular ferrite equiaxed structures G4Si1 welds, well small volume fraction pearlite along boundaries. Analysis AM70 welds found ferrite, martensite, bainite structures. Mechanical testing both materials hardness decreased with increase result decrease rate. higher yield lower elongation failure was observed parts printed using energy input. findings from this work can support automated parameter tuning control and, turn, parts.