Effect of Welding Heat on Residual Stress in Butt Welded Zone of Medium-Diameter Pipe

The weld overlay process has been developed and applied to repair of nuclear reactor pipe girth welds for many years in BWR plants. The objectives of such repairs were to induce compressive axial residual stresses on the pipe inside surface, as well as increase the pipe thickness with a weld material that is not susceptible to stress-corrosion cracking. Hence, understanding the residual stress distribution is important to evaluate the reliability of pipe joints with weld overlay repairs. In this paper, a six-inch diameter Schedule 120 stainless steel pipe with an overlay thickness of 7.87 mm (0.31 inch) was picked as a validation case. Weld sequencing effects were thoroughly studied. The residual stresses were calculated by using thermal elasto-plastic finite-element analysis (FEA). After comparing results using different weld sequences, it was found that the calculated weld residual stresses on ID surface were very sensitive to weld sequencing in FE analyses as well as internal cooling rate. The influence of the weld sequencing was relatively secondary to the pipe distortion. An optimum (producing compressive residual stress on the ID surface) weld sequencing was obtained and applied to a 711.2 mm (28-inch) diameter pipe-to-elbow girth weld with an overlay thickness of 24.9 mm (0.98 inch) and a pipe thickness of 29.5 mm (1.16 inch).

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Analytical Study of Residual Stress Improvement Method, Delta-T Process for Small- Diameter Pipe

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.78.976 ◽

2012 ◽

Vol 78 (791) ◽

pp. 976-988

Author(s):

Masaki TSURUKI ◽

Satoru AOIKE ◽

Shinobu OKIDO ◽

Yuka FUKUDA ◽

Naohiko ORITANI

Keyword(s):

Residual Stress ◽

Analytical Study ◽

Small Diameter ◽

Diameter Pipe ◽

Improvement Method

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Residual Stress Analysis by Simplified Inherent Strain at Welded Pipe Junctures in a Pressure Vessel

Journal of Pressure Vessel Technology ◽

10.1115/1.2883714 ◽

1999 ◽

Vol 121 (4) ◽

pp. 353-357 ◽

Cited By ~ 21

Author(s):

M. Mochizuki ◽

M. Hayashi ◽

T. Hattori

Keyword(s):

Residual Stress ◽

Pressure Vessel ◽

Welded Joint ◽

Three Dimensional ◽

Small Diameter ◽

Welding Residual Stress ◽

The Finite Element Method ◽

Diameter Pipe ◽

Welded Pipe ◽

Inherent Strain

We present a new and simplified method of estimating residual stress in welded structures by using inherent strain. The method makes use of elastic analysis by means of the finite element method and is used to calculate the residual stress in complicated three-dimensional structures efficiently. The inherent strain distribution in a welded joint of a small-diameter pipe penetrating a pressure vessel was assumed to be a simple distribution, and the residual stress was calculated. Inherent strain distributions were inferred from those of welded joints with simple shapes. The estimated residual stress using these inferred inherent strains agrees well with the measurements of a mock-up specimen. The proposed method is a simple way to estimate welding residual stress in three-dimensional structures of complicated shapes.

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1030 Analytical Survey of Use of Heat Treatment to Reduce the Residual Stress of Small-Diameter Pipe

The Proceedings of the Materials and Mechanics Conference ◽

10.1299/jsmemm.2010.1258 ◽

2010 ◽

Vol 2010 (0) ◽

pp. 1258-1259

Author(s):

Masaki TSURUKI ◽

Satoshi AOIKE ◽

Shinobu OOKIDO ◽

Yuka FUKUDA ◽

Naohiko ORITANI ◽

...

Keyword(s):

Heat Treatment ◽

Residual Stress ◽

Small Diameter ◽

Diameter Pipe

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1029 Study on the Residual Stress Improvement Method for Small Diameter Pipe (1) : Experimental Survey of the Residual Stress Improvement

The Proceedings of the Materials and Mechanics Conference ◽

10.1299/jsmemm.2010.1255 ◽

2010 ◽

Vol 2010 (0) ◽

pp. 1255-1257

Author(s):

Satoru AOIKE ◽

Masaki TSURUKI ◽

Shinobu OOKIDO ◽

Yuka FUKUDA ◽

Naohiko ORITANI ◽

...

Keyword(s):

Residual Stress ◽

Small Diameter ◽

Diameter Pipe ◽

Improvement Method ◽

Experimental Survey

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SCC Potential Assessment in Butt Welded Zone of Medium-Diameter Pipe

The Proceedings of the Materials and Mechanics Conference ◽

10.1299/jsmemm.2019.os1304 ◽

2019 ◽

Vol 2019 (0) ◽

pp. OS1304

Author(s):

Yosuke NAKANO ◽

Yoshiteru TOYOSHIMA ◽

Yuya ISHII ◽

Yuka MIYATA ◽

Nobuyoshi YANAGIDA

Keyword(s):

Diameter Pipe ◽

Medium Diameter

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TEM investigations of surface residual stress relaxation in A12O3 and Al2O3-SiC nanocomposite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170876 ◽

1994 ◽

Vol 52 ◽

pp. 628-629

Author(s):

J. Fang ◽

H. M. Chan ◽

M. P. Harmer

Keyword(s):

Residual Stress ◽

Single Phase ◽

Stress Relief ◽

Stress Recovery ◽

Surface Residual Stress ◽

Microscopic Mechanism ◽

Sic Particles ◽

Annealing Procedure ◽

The Difference ◽

Nano Size

It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.

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Residual stress measurements and modeling of built-up Box-T sections

Thin-Walled Structures ◽

10.1016/j.tws.2020.107336 ◽

2021 ◽

Vol 160 ◽

pp. 107336

Author(s):

Ziqian Zhang ◽

Gang Shi ◽

Xuesen Chen ◽

Lijun Wang ◽

Le Zhou

Keyword(s):

Residual Stress ◽

Stress Measurements

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Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

Mechanics & Industry ◽

10.1051/meca/2020061 ◽

2020 ◽

Vol 21 (5) ◽

pp. 505

Author(s):

Yousef Ghaderi Dehkordi ◽

Ali Pourkamali Anaraki ◽

Amir Reza Shahani

Keyword(s):

Residual Stress ◽

Cyclic Loading ◽

Stress Relaxation ◽

Stress Amplitude ◽

Cyclic Plasticity ◽

Mean Stress ◽

Effective Parameters ◽

Perfect Plasticity ◽

Residual Stress Relaxation ◽

Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

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