Effect of pulse scheme on the microstructural evolution, residual stress state and mechanical performance of resistance spot welded DP1000-GI steel

Abstract Joining an additively manufactured component to a forged or cast part through welding processes has recently attracted the attention of engineers and scientists. This technique integrates the technical benefits of additive manufacturing (AM) technology with conventional processes that may be more cost-efficient. In this paper, the effect of residual stresses on the mechanical performance of a hybrid welded pipe joint connecting an additively manufactured maraging steel (MS1) pipe segment with a conventional P20 steel tube having an equivalent outside diameter was studied. A sequentially coupled thermo-mechanical continuum finite element (FE) modeling procedure to predict the residual stress state on circumferential pipe hybrid MS1-P20 joints subjected to multi-axial loads was developed and validated. Available experimental data on a welded pipe joint with conventional stainless steel (SUS304) were used to calibrate the model. The FE modeling procedures were further validated for the hybrid MS1-P20 joint. The predicted residual stress state was mapped on the pipe joint with equal and unequal wall thickness joint transitions. The mechanical performance of these pipe joints was evaluated with the application of internal pressure, uniaxial tension, and flexural loads. The major contribution of this study was the proposition of a new concept of hybrid joints, where a significant transition of the load was expected. The new hybrid joint concept was presented to meet the existing design criteria requirements without sacrificing other parameters (e.g., component weight and manufacturing expense) and facilitate the production of hybrid components using AM techniques.

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Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽

10.3390/pr9061021 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1021

Author(s):

Yunzhao Li ◽

Huaping Tang ◽

Ruilin Lai

Keyword(s):

Mechanical Properties ◽

Failure Modes ◽

Mechanical Performance ◽

Strong Dependence ◽

High Strength ◽

Weld Nugget ◽

Resistance Spot ◽

Pull Out ◽

Cross Tension ◽

Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

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Influence of Steel Grain Size on Residual Stress in Grinding Processing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.2389 ◽

2010 ◽

Vol 638-642 ◽

pp. 2389-2394 ◽

Cited By ~ 3

Author(s):

Masahide Gotoh ◽

Katsuhiro Seki ◽

M. Shozu ◽

Hajime Hirose ◽

Toshihiko Sasaki

Keyword(s):

Mechanical Properties ◽

Residual Stress ◽

Grain Size ◽

Stress State ◽

Mechanical Grinding ◽

Fine Grained ◽

Residual Stress State ◽

Analysis Methods ◽

Average Grain Size ◽

Fine Grained Steels

The fine-grained rolling steels NFG600 and the conventional usual rolling steels SM490 were processed by sand paper polishing and mechanical grinding to compare the residual stress generated after processing. The average grain size of NFG600 and SM490 is 3 μm and 15μm respectively. Therefore improvement of mechanical properties for such fine-grained steels is expected, it is important to understand the residual stress state of new fine-grained materials with processing. In this study, multi axial stresses of two kinds of specimens after polishing and grinding were measured by three kinds of analysis methods including cos-ψ method. As a result, as for σ33, the stress of NFG was compression, though that of SM490 was tension.

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About Residual Stress State of Castings: The Case of HPDC Parts and Possible Advantages through Semi-Solid Processes

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.327.272 ◽

2022 ◽

Vol 327 ◽

pp. 272-278

Author(s):

Elisa Fracchia ◽

Federico Simone Gobber ◽

Claudio Mus ◽

Yuji Kobayashi ◽

Mario Rosso

Keyword(s):

Residual Stress ◽

Stress State ◽

Residual Stresses ◽

Casting Process ◽

Ray Method ◽

Premature Failure ◽

Thin Walls ◽

Residual Stress State ◽

Semi Solid ◽

Pressure Die Casting

Nowadays, one of the most crucial focus in the aluminium-foundry sector is the production of high-quality castings. Mainly, High-Pressure Die Casting (HPDC) is broadly adopted, since by this process is possible to realize aluminium castings with thin walls and high specific mechanical properties. On the other hand, this casting process may cause tensile states into the castings, namely residual stresses. Residual stresses may strongly affect the life of the product causing premature failure of the casting. Various methods can assess these tensile states, but the non-destructive X-Ray method is the most commonly adopted. Namely, in this work, the residual stress analysis has been performed through Sinto-Pulstec μ-X360s. Detailed measurements have been done on powertrain components realized in aluminium alloy EN AC 46000 through HPDC processes to understand and prevent dangerous residual stress state into the aluminium castings. Furthermore, a comparison with stresses induced by Rheocasting processes is underway. In fact, it is well known that Semi-Solid metal forming combines the advantages of casting and forging, solving safety and environmental problems and possibly even the residual stress state can be positively affected.

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Analysis of Residual Stress State in Thermal Barrier Coatings

Fracture Mechanics of Ceramics ◽

10.1007/978-1-4757-4019-6_13 ◽

2002 ◽

pp. 169-178 ◽

Cited By ~ 1

Author(s):

T.-J. Chuang ◽

E. R. Fuller

Keyword(s):

Residual Stress ◽

Stress State ◽

Thermal Barrier Coatings ◽

Thermal Barrier ◽

Barrier Coatings ◽

Residual Stress State

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Effects of deposition temperature and thermal cycling on residual stress state in zirconia-based thermal barrier coatings

Surface and Coatings Technology ◽

10.1016/s0257-8972(99)00341-2 ◽

1999 ◽

Vol 120-121 ◽

pp. 103-111 ◽

Cited By ~ 115

Author(s):

V. Teixeira ◽

M. Andritschky ◽

W. Fischer ◽

H.P. Buchkremer ◽

D. Stöver

Keyword(s):

Residual Stress ◽

Stress State ◽

Thermal Cycling ◽

Thermal Barrier Coatings ◽

Deposition Temperature ◽

Thermal Barrier ◽

Barrier Coatings ◽

Residual Stress State

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Analysis of the Influence of Surface Modifications on the Fatigue Behavior of Hot Work Tool Steel Components

Materials ◽

10.3390/ma14237324 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7324

Author(s):

Thomas Wild ◽

Timo Platt ◽

Dirk Biermann ◽

Marion Merklein

Keyword(s):

Residual Stress ◽

Stress State ◽

Surface Integrity ◽

Fatigue Behavior ◽

Hot Forging ◽

Surface Modifications ◽

Bending Test ◽

Fatigue Properties ◽

Machining Processes ◽

Residual Stress State

Hot work tool steels (HWS) are widely used for high performance components as dies and molds in hot forging processes, where extreme process-related mechanical and thermal loads limit tool life. With the functionalizing and modification of tool surfaces with tailored surfaces, a promising approach is given to provide material flow control resulting in the efficient die filling of cavities while reducing the process forces. In terms of fatigue properties, the influence of surface modifications on surface integrity is insufficiently studied. Therefore, the potential of the machining processes of high-feed milling, micromilling and grinding with regard to the implications on the fatigue strength of components made of HWS (AISI H11) hardened to 50 ± 1 HRC was investigated. For this purpose, the machined surfaces were characterized in terms of surface topography and residual stress state to determine the surface integrity. In order to analyze the resulting fatigue behavior as a result of the machining processes, a rotating bending test was performed. The fracture surfaces were investigated using fractographic analysis to define the initiation area and to identify the source of failure. The investigations showed a significant influence of the machining-induced surface integrity and, in particular, the induced residual stress state on the fatigue properties of components made of HWS.

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