Failure analysis and the cold crack formation mechanism for the QP1180 steel welded joint

Ding, Kai; Wang, Yuanfang; Lei, Ming; Wei, Tao; Wu, Guanzhi; Zhang, Yuanheng; Pan, Hongyan; Gao, Yulai

doi:10.1016/j.engfailanal.2021.105767

Cited by 4 publications

(4 citation statements)

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“…The greater the ratio of the cross-sectional area of the element to the cross-sectional area of the welds in a given plane, the lower the longitudinal shrinkage. The force of contraction is distributed over a larger area and thus the longitudinal elastic deformation of the element will be smaller [ 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

“…It was also observed that the application of these processes allows us to obtain a very regular profile of the joint, which in turn translates into negligible deformation of the joined elements. It is an important parameter in the case of bonding thin-walled elements in order to minimize welding deformations of the construction [ 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

“…However, based on studies using only a light microscope, its role in morphology has not yet been determined. It can only be assumed that due to the probable presence of coniferous ferrite in these areas, the microstructure will be bainitic [ 26 , 27 , 28 , 29 , 30 ].…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the analyzed material is cold-rolled steel, and therefore contains a high density of dislocation, which allows us to analyze the possibility of healing or even recrystallization processes in a more classic approach. Of course, it should be noted that high-strain recrystallization leads to grain refinement, and, thus, material strengthening, and requires thermodynamic conditions for nucleation and new grain growth, which may be difficult to achieve with rapidly changing processes [ 26 , 27 , 28 , 29 , 30 ]. Verification of the indicated hypotheses is possible through more detailed microstructure studies, especially with the use of transmission electron microscopy (TEM), which is planned at the next stages of the research.…”

Section: Resultsmentioning

confidence: 99%

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Microstructure and Mechanical Properties of Joints Depending on the Process Used

et al. 2022

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Today, numerous design solutions require joining thin-walled sheets or profiles as the traditional methods of welding with a consumable electrode in gas shielding, most often used in production processes, do not work well. The reason for this is that a large amount of heat is supplied to the joint, causing numerous welding deformations, defects, and incompatibilities. Moreover, the visual aspect of the connections made more and more often plays an equally crucial role. Therefore, it is important to look for solutions and compare different joining processes in order to achieve production criteria. The paper compares the properties of a 1.5 mm thick steel sheet joined by the manual and robotic MAG 135 and 138 welding process, manual and robotic laser welding, CMT welding with the use of solid or flux-cored wire, and butt welding. The macro- and microstructure, as well as the microhardness distribution of individual regions of the joints, were analyzed depending on the type of joining technology used. Furthermore, the mechanical properties of individual zones of joints were investigated with the use of a digital image correlation system. On the basis of the obtained test results, it was found that the joints made by the processes of manual laser welding and butt welding were characterized by a very regular weld shape, the smallest joint width, and greater grain refinement compared to other analyzed processes. Moreover, this method was characterized by the narrowest zone of hardness increase, only 3 mm, compared to, e.g., a joint made in the process of robotic welding CMT, for which this zone was more than twice as wide. Furthermore, the heat-affected zone for the joints made in this way, in relation to the welds produced by the MAG 135/138 method, was, respectively, 2 and 2.7 times smaller.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%