Residual stress state behaviour under fatigue loading in duplex stainless steel

Pedrosa, P.D.S; Rebello, J. M. A.; Fonseca, Maria Cindra

doi:10.1177/0309324711400499

Cited by 5 publications

(4 citation statements)

References 7 publications

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“…In other words, the distributions presented in Eqs. (2) and (3) are such that their standard deviations are: b = S (b) 3 and a = S (a) 3 . The fifth line of the algorithm excludes any possibility of sampling stresses σ (a) which would correspond to an increase in RS levels.…”

Section: Reduction Of Residual Stress: Uncertaintiesmentioning

confidence: 99%

“…The first is that the presence of tensile RS is an issue of concern for the metal-mechanical industry and consequently for any engineering design. This is due to the fact that tensile RS has deleterious effects on the fatigue life and stress corrosion cracking of structural components [2,3]. The second is that compressive RS provides benefits mainly by limiting the nucleation and propagation of cracks.…”

Section: Introductionmentioning

confidence: 99%

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Residual stress relief of welded joints by mechanical vibrations

Chuvas

Castello

Fonseca

2016

J Braz. Soc. Mech. Sci. Eng.

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List of symbols ∆ σ Residual stress reduction level (%) σ (b) Stress measured before the vibratory motion σ (a) Stress measured after the vibratory motion σ − S σ , −S σ , (1 − α) × 100 % confidence interval for σ 2 b Variance of the random variable σ (b) 2 a Variance of the random variable σ (a) S (b) σ Half-bandwidth of the confidence interval for the measured stress before the vibratory motion S (a) σ Half-bandwidth of the confidence interval for the measured stress after the vibratory motion π(z) Pdf of the random variable z z ∼ N µ, 2 Z follows a Gaussian distribution with mean μ and variance 2 RS Residual stress HAZ Heat-affected zone PAW Plasma arc welding GTAW Gas tungsten arc welding FZ Fused zone Abstract Stress relief treatment based on mechanical vibrations is a technology that stands out for being an alternative to conventional thermal treatments and also due to its effectiveness for materials with heterogeneous structures. In this context, the application of this technique in welded joints has great potential for reducing residual stresses. This research presents some analyses of the effectiveness of surface residual stress relief treatment by mechanical vibrations using random excitations applied on plasma welded joints. Residual stresses were analysed by the X-ray diffraction technique with the sin 2 ψ method. Measurement uncertainties are taken into account in the computation of the reduction of residual stresses via Monte Carlo simulation analyses. A significant reduction in the residual stresses magnitudes, around 40 %, in the longitudinal direction was observed after the application of mechanical vibration treatments stress. In the transversal direction, most of the test specimens presented reduction levels around 20 %.

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Section: Reduction Of Residual Stress: Uncertaintiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Residual stress relief of welded joints by mechanical vibrations

Chuvas

Castello

Fonseca

2016

J Braz. Soc. Mech. Sci. Eng.

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“…Regardless of the type of occurring stresses, their action al-ways causes elastic deformation of the crystal lattice. It can be noticed that internal stresses play a significant role in the process of deformation and initiation of microdamage (Almer et al, 2000;Meng et al, 2017;Mughrabi, 2013;Pedrosa et al, 2011;Sangid, 2013). It is believed that the direct cause of internal stresses in the polycrystalline body is the geometric incompatibility of the deformation caused by the anisotropy of the mechanical properties of individual crystals.…”

Section: Introductionmentioning

confidence: 99%

Design of The Vibrostabilisation Stand For Reducing Residual Stresses in Discs Used In The Construction of Multi-Plate Clutches and Brakes

Jaroszewicz

Łukaszewicz

Antonyuk

2019

Acta Mechanica Et Automatica

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Heavy-duty, oil-cooled brake discs (MMOTs) are often used in heavy-duty brake systems manufactured by companies such as Caterpilar, Clark, Komatsu and Liebherr. These discs are usually made of special steels, and in most cases, the flatness of the working surfaces should not exceed 0.15–0.30 mm. Although the technological processes of friction disc production include several stages of heat treatment and grinding, the required accuracy is not achieved in some cases. In addition, the remaining residual stresses lead to the deformation of the discs during their lifetime. In production practice, three methods are used to reduce residual stresses: thermo-fixing, dynamic stabilisation and vibratory stabilisation consisting in bringing discs to transverse resonance vibrations and maintaining resonance until significant stress reduction. The article proposes a method of stabilising the discs using the resonance phenomenon at the first few frequencies. In this article, Cauchy’s function method and characteristic series method are used to develop solution value problem for clamped circular plates with discrete inclusions as concentrated masses and springs. Calculation methods for quick estimation of the own frequency of discs with additional ring mass enabling the use of low power vibration inductors are presented. The use of a special membrane and a pneumatic cushion in the construction of the stand allows to induce vibrations of higher frequencies.

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“…As welding is one of the main industrial processes for fabrication of structures and pipelines, the knowledge of residual stress (RS) induced by this process is extremely important because the mechanical properties of the welded components, such as fatigue and thermal fatigue resistance, are not only determined by the microstructures present in the joint, but also by residual stresses heterogeneously introduced in the thermal cycle during the process 7,8 . In this context, the construction of welding pipelines of high integrity and strength are necessary: in order to achieve safe operation in the power plant, which can be compromised by the presence of residual stresses, which can reach values very close to the material yield strength at determinate regions, decreasing the service life [9][10][11] .…”

Section: Introductionmentioning

confidence: 99%