The Structure of the Welded Joints between High-Strength Steel USIBOR 22MnB5 and Mild Steel H340LAD+Z140-M-B-O Made by Resistance Spot Welding

Sejč, Pavol; Belanová, Judita; Emmer, Štefan

doi:10.17559/tv-20160928104619

Cited by 1 publication

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“…Hot-stamped components need to be joined together to produce complex shapes, and 22MnB5 has good spot weldability for both similar and dissimilar welds. The structure of the resistance spot welded joint between Al-Si coated 22MnB5 and zinc (Zn) coated H340LAD was investigated by Sejč et al [7]. Laser welding is also a suitable technology for press-hardened steel welding.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Characterization of Laser Weld of Hot-Stamped Al-Si Coated 22MnB5 and Modification of Weld Properties by Hybrid Welding

et al. 2021

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The presence of Al-Si coating on 22MnB5 leads to the formation of large ferritic bands in the dominantly martensitic microstructure of butt laser welds. Rapid cooling of laser weld metal is responsible for insufficient diffusion of coating elements into the steel and incomplete homogenization of weld fusion zone. The Al-rich regions promote the formation of ferritic solid solution. Soft ferritic bands cause weld joint weakening. Laser welds reached only 64% of base metal's ultimate tensile strength, and they always fractured in the fusion zone during the tensile tests. We implemented hybrid laser-TIG welding technology to reduce weld cooling rate by the addition of heat of the arc. The effect of arc current on weld microstructure and mechanical properties was investigated. Thanks to the slower cooling, the large ferritic bands were eliminated. The hybrid welds reached greater ultimate tensile strength compared to laser welds. The location of the fracture moved from the fusion zone to a tempered heat-affected zone characterized by a drop in microhardness. The minimum of microhardness was independent of heat input in this region.

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Section: Introductionmentioning

confidence: 99%