Hot-rolled Steel Sheet with Excellent Flash Weldability for Automobile Wheel Rim Use

Yamauchi, Nobuyuki; Kunishige, Kazutoshi; Taka, Takao; Nagao, Noriaki

doi:10.2355/tetsutohagane1955.68.9_1421

Cited by 5 publications

(2 citation statements)

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“…[28] The phenomenon was recognized as HAZ softening, and first identified when dual-phase steels were flash butt welded for wheel rim applications. [29] It was found that failure consistently occurs at the prior softened HAZ, which is caused by the tempering of martensite in the HAZ during the welding process. It is thus, imperative to have a proper understanding of the underlying mechanism of this observed softening in the deposit.…”

Section: A Macrostructure and Deposit Morphologymentioning

confidence: 99%

Microstructural Analyses of ATI 718Plus® Produced by Wire-ARC Additive Manufacturing Process

Asala

Khan

Andersson

et al. 2017

Metall Mater Trans A

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A detailed microstructural study of ATI 718Plus superalloy produced by the wire-arc additive manufacturing (WAAM) process was performed through the use of scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron probe micro-analysis (EPMA), and electron backscatter diffraction (EBSD). Extensive formation of eutectic solidification microconstituents including Laves and MC-type carbide phases, induced by micro-segregation, are observed in the build of the alloy in the as-deposited condition. Notwithstanding the significant segregation of niobium (Nb), which has been reported to promote the formation of the d-phase in ATI 718Plus, only g-phase particles are observed in the deposit. Excessive precipitation of g-phase particles is found to be linked to Laves phase particles that are partially dissolved in the deposit after post-deposition heat treatment (PDHT). The EBSD analysis shows a high textured build in the h100i directions with only a few misoriented grains at the substrate-deposit boundary and the top of the deposit. Investigation on the hardness of the build of the alloy, in the as-deposited condition, showed a softened zone about 2 mm wide at the deposited metal heat affected zone (DMHAZ), which has not been previously reported and potentially damaging to the mechanical properties. An extensive analysis with the use of both microstructural characterization tools and theoretical calculations shows that the DMHAZ has the lowest volume fraction of strengthening precipitates (c¢ and c¢¢) in terms of their number density, which therefore induces the observed softness. Delayed re-precipitation kinetics and the extent of the precipitation of c¢ and c¢¢ in the DMHAZ which is related to the diffusion of segregated solute elements from the interdendritic regions are attributed to this phenomenon. The microstructural analyses discussed in this work are vital to adequate understanding of properties of ATI 718Plus produced by the additive manufacturing process technique.

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Section: A Macrostructure and Deposit Morphologymentioning

confidence: 99%

Microstructural Analyses of ATI 718Plus® Produced by Wire-ARC Additive Manufacturing Process

Asala

Khan

Andersson

et al. 2017

Metall Mater Trans A

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“…This phenomenon, known as HAZ softening, was first reported when DP steels were flash butt welded for wheel rim applications. 7,8) In these situations, it was reported that failures were occurring in the softer tempered or sub-critical area of the HAZ.…”

Section: Introductionmentioning

confidence: 99%

Predicting Transient Softening in the Sub-Critical Heat-Affected Zone of Dual-Phase and Martensitic Steel Welds

et al. 2013

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To improve vehicle fuel economy and crash worthiness the automotive industry has been redesigning parts from advanced high strength steels such as dual-phase and martensitic steels. These steels have high strengths with the higher formability characteristics when compared to lower strength conventional steels of similar ductility. These steels derive their unique properties from their complex microstructures containing ferrite and martensite. During assembly welding, the martensite within the sub-critical region of the heat-affected zone tempers, which locally reduces mechanical properties. Although this phenomenon is well studied, it has yet to be quantified. The present work proposes a technique to measure the softening kinetics of dual-phase and martensite steels using rapid isothermal tempering. The resulting model was then validated by predicting the heat-affect zone softening that occurs in laser and resistance spot welds as well as by comparing the microstructures of the rapid tempered samples to the microstructures found in the sub-critical heat-affected zone of welded samples.

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Gas metal arc weldability of 1.5 GPa grade martensitic steels

et al. 2018

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Hot-rolled Steel Sheet with Excellent Flash Weldability for Automobile Wheel Rim Use

Cited by 5 publications

References 0 publications

Microstructural Analyses of ATI 718Plus® Produced by Wire-ARC Additive Manufacturing Process

Microstructural Analyses of ATI 718Plus® Produced by Wire-ARC Additive Manufacturing Process

Predicting Transient Softening in the Sub-Critical Heat-Affected Zone of Dual-Phase and Martensitic Steel Welds

Gas metal arc weldability of 1.5 GPa grade martensitic steels

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