Matching effect on fatigue crack growth behaviour of high-strength steels GMA welded joints

Lukács, János; Dobosy, Ádám

doi:10.1007/s40194-019-00768-3

Cited by 20 publications

(7 citation statements)

References 14 publications

(12 reference statements)

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“…Within the weldability challenges, the effect of the limited filler metal choice and the mismatch effect on the static and dynamic behavior of the welded joint cannot be neglected. Due to the higher crack sensitivity of the weld and HAZ microstructure and the possible cyclic loading conditions in mobile structures, fracture mechanics approach is recommended to be used during the structural and technological design [12,13].…”

Section: Introductionmentioning

confidence: 99%

Effect of Welding Heat Input on Simulated HAZ Areas in S960QL High Strength Steel

Gáspár

2019

Metals

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When the weldability of high strength steels is analyzed, it is the softening in the heat-affected zone (HAZ) that is mostly investigated, and the reduction of toughness properties is generally less considered. The outstanding toughness properties of quenched and tempered high strength steels cannot be adequately preserved during the welding due to the unfavorable microstructural changes in the HAZ. Relevant technological variants (t8/5 = 2.5–100 s) for arc welding technologies were applied during the HAZ simulation of S960QL steel (EN 10025-6) in a Gleeble 3500 physical simulator, and the effect of cooling time on the critical HAZ areas of single and multipass welded joints was analyzed. Thermal cycles were determined according to the Rykalin 3D model. The properties of the selected coarse-grained (CGHAZ), intercritical (ICHAZ) and intercritically reheated coarse-grained (ICCGHAZ) zones were investigated by scanning electron microscope, macro and micro hardness tests and instrumented Charpy V-notch pendulum impact tests. The examined HAZ subzones indicated higher sensitivity to the welding heat input compared to conventional structural steels. Due to the observed brittle behavior of all subzones in the whole t8/5 range, the possible lowest welding heat input should be applied in order to minimize the volume of HAZ that does not put fulfillment of the allowed maximal (450 HV10) hardness at risk and does not lead to the formation of cold cracks.

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Section: Introductionmentioning

confidence: 99%

Effect of Welding Heat Input on Simulated HAZ Areas in S960QL High Strength Steel

Gáspár

2019

Metals

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“…The UM weldments usually own higher toughness, higher hydrogen cracking resistance, and smaller residual stress. In the investigation of FCGR of S960M high strength steel weldments, EM's FCGRs are slower than those of UM, 51 which exhibits that EM's fatigue crack resistance is higher than that of UM. Similar results can be found in our study.…”

Section: Discussionmentioning

confidence: 96%

Fatigue fracture assessment of 10CrNi3MoV welded load‐carrying cruciform joints considering mismatch effect

Song

Liu

et al. 2021

Fatigue Fract Eng Mat Struct

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Fatigue experiments and numerical simulations based on the linear elastic fracture mechanics (LEFM) theory were conducted on the evenmatched (EM) and undermatched (UM) 10CrNi3MoV load-carrying cruciform welded joints (LCWJs). The study firstly experimentally investigated the fatigue crack growth rate (FCGR) of base metal, EM, and UM weldments. The corresponding Paris parameters as essential input data are provided to assess the fatigue crack propagation behavior for weld toe and weld root failure caused by notch stress concentration variations. On the one hand, the stress intensity factors (SIFs) at weld toe and weld root were calculated considering the effects of LCWJ specimen geometries, initial crack types, and sizes. The comparisons between simulated results and standards analytical solutions were executed, which exhibit good accordance. It proved that the fatigue fracture simulation procedure based on LEFM is appropriate for the fatigue assessment of LCWJs. Eventually, it conducted the parametric analysis by predicted S-N curves, which included in the weld length, initial crack shape, initial crack size, penetration length, and materials fracture parameter, to explore some safety assessment reference lines for both failure modes of LCWJ.

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“…The quenched and tempered group is the most frequently-used high-strength structural steel category, and S960QL is the highest grade according to the EN 10025-6 standard, although nowadays higher-strength grades are available but not yet classified using the standard. HSS can make a significant contribution to supporting sustainable development by reducing the weight of structures and vehicles with increased payload capacity, and by lowering fuel consumption and CO 2 emissions [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

An Approach to Assessing S960QL Steel Welded Joints Using EBW and GMAW

Sisodia

Gáspár

2022

Metals

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In recent years, ultra-high-strength structural (UHSS) steel in quenched and tempered (Q+T) conditions, for example, S960QL has been found in wider application areas such as structures, cranes, and trucks due to its extraordinary material properties and acceptable weldability. The motivation of the study is to investigate the unique capabilities of electron beam welding (EBW) compared to conventional gas metal arc welding (GMAW) for a deep, narrow weld with a small heat-affected zone (HAZ) and minimum thermal distortion of the welded joint without significantly affecting the mechanical properties. In this study, S960QL base material (BM) specimens with a thickness of 15 mm were butt-welded without filler material at a welding speed of 10 mm/s using the high-vacuum (2 × 10−4 mbar) EBW process. Microstructural characteristics were analyzed using an optical microscope (OM), a scanning electron microscope (SEM), fractography, and an electron backscatter diffraction (EBSD) analysis. The macro hardness, tensile strength, and instrumented Charpy-V impact test were performed to evaluate the mechanical properties. Further, the results of these tests of the EBW joints were compared with the GMAW joints of the same steel grade and thickness. Higher hardness is observed in the fusion zone (FZ) and the HAZ compared to the BM but under the limit of qualifying the hardness value (450 HV10) of Q+T steels according to the ISO 15614-11 specifications. The tensile strength of the EBW-welded joint (1044 MPa) reached the level of the BM as the specimens fractured in the BM. The FZ microstructure consists of fine dendritic martensite and the HAZ predominantly consists of martensite. Instrumented impact testing was performed on Charpy-V specimens at −40 °C, which showed the brittle behavior of both the FZ and HAZ but to a significantly lower extent compared to GMAW. The measured average impact toughness of the BM is 162 J and the average impact toughness value of the HAZ and FZ are 45 ± 11 J and 44 ± 20 J, respectively.

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Matching effect on fatigue crack growth behaviour of high-strength steels GMA welded joints

Cited by 20 publications

References 14 publications

Effect of Welding Heat Input on Simulated HAZ Areas in S960QL High Strength Steel

Effect of Welding Heat Input on Simulated HAZ Areas in S960QL High Strength Steel

Fatigue fracture assessment of 10CrNi3MoV welded load‐carrying cruciform joints considering mismatch effect

An Approach to Assessing S960QL Steel Welded Joints Using EBW and GMAW

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