Liquid zinc penetration induced intergranular brittle cracking in resistance spot welding of galvannealed advanced high strength steel

Murugan, Siva Prasad; Jeon, Jong Bae; Ji, Changwook; Park, Yeong-Do

doi:10.1007/s40194-020-00975-3

Cited by 19 publications

(6 citation statements)

References 42 publications

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“…The assumption of LME as crack mechanism is based on (i) the avoidance of these cracks by removing the brass layer from the surface, (ii) the distinct intergranular crack propagation with deposits of melted material from the brass layer, and (iii) the location of the cracks on the surfaces of the sheets. Furthermore, (iv) the crack shape and the Cu deposits on the crack flanks (see Figures 5 and 6) on both materials indicate LME [32,38]. According to Savage et al, LMEs can be caused by copper deposits, especially in metals with FCC structure [39,40].…”

Section: Discussionmentioning

confidence: 94%

“…It is also assumed that the load due to shrinkage stress, especially in weld direction, is then high enough to cause the separation of the grains either due to the liquid phase or due to embrittlement at the grain boundaries. Figure 9d shows the cracking mechanism for LME, which would be likely for the EDM surfaces [32,[38][39][40]. Note that the exact LME mechanism has not yet been conclusively clarified.…”

Section: Discussionmentioning

confidence: 99%

“…On the one hand, it could be conventional hot cracking in the form of liquation cracks or ductility dip cracks (DDC) [30]. On the other hand, the cracks could also be initiated by a liquid metal embrittlement (LME) mechanism, which mainly occurs in, e.g., Zn-coated materials [31,32]. Cold cracking can be ruled out since both alloys have an increased elongation at fracture at temperatures below 400 • C [33] and, in addition, the CoCrFeMnNi alloy does not tend to strong hydrogen-induced embrittlement [34].…”

Section: Light Optical Microscopymentioning

confidence: 99%

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Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys

Richter

Giese

Rhode

et al. 2021

JMMP

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Multi-element systems with defined entropy (HEA—high entropy alloy or MEA—medium entropy alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcoming of the trade-off between high strength and ductility. Thus, the synthesis, the resulting microstructures, and properties of HEA have been primarily investigated so far. In addition, processing is crucial to achieve a transfer of potential HEA/MEA materials to real applications, e.g., highly stressed components. Since fusion welding is the most important joining process for metals, it is of vital importance to investigate the weldability of these materials. However, this has rarely been the subject of research to date. For that reason, in this work, the weldability depending on the surface preparation of a CoCrFeMnNi HEA and a CoCrNi MEA for TIG welding is investigated. The fusion welding of longer plates is described here for the first time for the CoCrNi alloy. The welds of both materials showed distinct formation of cracks in the heat affected zone (HAZ). Optical and scanning electron microscopy analysis clearly confirmed an intergranular fracture topography. However, based on the results, the crack mechanism cannot be conclusively identified as either a liquid metal embrittlement (LME) or hot cracking-like liquid film separation.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Light Optical Microscopymentioning

confidence: 99%

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Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys

Richter

Giese

Rhode

et al. 2021

JMMP

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“…[12][13][14][15][16] Although the mechanism inducing LME is still debatable in existing studies as either Zn grain boundary diffusion or liquid grain boundary penetration leading to the LME, it is widely believed that LME is a kind of intergranular cracks generally happens at high temperatures above the melting point of coating, caused by the combined effect of liquid Zn and tensile stress. [17][18][19][20] Since LME is a not expected phenomenon resulting from the contact between the melt coating and steel substrate, so that the effects of coating and substrate steel types on the LME susceptibility are getting widely attentions. A hot tensile test and spot welding test are two common ways to evaluate LME susceptibility.…”

Section: Introductionmentioning

confidence: 99%

Comparative Investigation into the Liquid Metal Embrittlement Susceptibility during Resistance Spot Welding of Zn–Al–Mg and GI Coated Advanced High Strength Steels

Zhang

Cai

et al. 2023

ISIJ Int.

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In automotive industry, it is well known that cracks which are promoted by liquid metal embrittlement (LME) can occur during the resistance spot welding (RSW) of zinc-coated advanced high-strength steels (AHSS). The coating type is supposed to be one of the factors impacting LME susceptibility. Recently, Zn-Al-Mg coating is gaining increasing focus because of its enhanced corrosion resistance compared to traditional Galvanized (GI) coating. However, there is a lack of research on assessing the influence of this coating on LME susceptibility. In this study, the LME susceptibility of Zn-Al-Mg and GI coated advanced high strength steels with similar microstructure and strength are compared by hot tensile tests and RSW. The results show that Zn-Al-Mg coated samples present a more significant ductility loss than that of GI coated ones in hot tensile test, and also there are more LME cracks with large length occur in Zn-Al-Mg coated RSW joints, indicating that Zn-Al-Mg coatings have a higher LME sensitivity. The high temperature phase evolution analysis results show that Fe-Zn intermetallic compounds formed in two coatings are different, indicating that there are lower level of Fe-Zn alloying reactions in Zn-Al-Mg coating. The inadequate Fe-Zn reactions potentially facilitate the direct contact between liquid Zn and steel substrate, leading Zn-Al-Mg coating to a higher LME susceptibility.

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“…The combination of phases with very different thermomechanical behaviors gives rise to a high microstructural complexity of the CP, bainite, ferrite and martensite [15], so the failure mechanisms of the RSW-welded joints of all these steels have not been studied in depth [16]. In addition, due to their high carbon equivalent content, problems related to the formation of martensite in the weld bead can occur during welding of these steels, therefore the search for the weldability lobe is of clear interest.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Process Parameters on the Quality and Efficiency of the Resistance Spot Welding Process of Advanced High-Strength Complex-Phase Steels

Morales-Sánchez

Collazo

Doval-Gandoy

2021

Metals

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In this study, the effects of electrical characteristics of an inverter combined with main welding parameters on the resistance spot weldability of advanced high strength steels (AHSS) CP1000 is investigated. The main welding parameters, current and time, were varied. The effects on the geometry and microstructure of the weld spot, the diameter of the weld pad, the hardness, the shear strength, and the efficiency of the process were studied, and the results were compared for two switching frequencies of the medium frequency converter. Furthermore, the weldability lobes were obtained as a function of the shear strength, for both frequencies. This work shows that the quality of the welding, in the established terms, is better when a lower frequency is used, even though the parameterization of the welding equipment can be easier for higher frequencies.

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Liquid zinc penetration induced intergranular brittle cracking in resistance spot welding of galvannealed advanced high strength steel

Cited by 19 publications

References 42 publications

Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys

Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys

Comparative Investigation into the Liquid Metal Embrittlement Susceptibility during Resistance Spot Welding of Zn–Al–Mg and GI Coated Advanced High Strength Steels

Influence of the Process Parameters on the Quality and Efficiency of the Resistance Spot Welding Process of Advanced High-Strength Complex-Phase Steels

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