A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part II: The Characteristics of Reduction of Welding Residual Stresses in Very Thick Joints During SR Treatment

1999 ◽  
Vol 121 (1) ◽  
pp. 11-16 ◽  
Author(s):  
K. Nakacho ◽  
Y. Ueda
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
Welded Joint ◽  
Uniaxial Stress ◽  
Stress Relief ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Creep Theory ◽  
Multiaxial Stress State ◽  
Further Development

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is considerably similar to that observed in the SR treatment of a joint. In this report, the stresses relaxed by SR treatment in a very thick welded joint are analyzed accurately by the finite element method based on thermal elastic-plastic-creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state are studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part IV: Applicability of the Simple Estimating Method for Stress-Relief Annealing of Thick Welded Joint

2002 ◽  
Vol 124 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Keiji Nakacho
Keyword(s):  
Stress State ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Welded Joint ◽  
Uniaxial Stress ◽  
Stress Relief ◽  
Pressure Vessels ◽  
Relaxation Phenomenon ◽  
Multiaxial Stress ◽  
Creep Theory

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of a very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon may be considerably similar to that observed in the SR treatment of a joint. In the second report, the stresses relaxed by SR treatment in a very thick welded joint were analyzed accurately by the finite element method based on thermal elastic-plastic creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state were studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex. In the third report, the estimating equations in multiaxial stress states were developed for the stress relaxation phenomenon in the thick welded joints, based on the foregoing characteristics. In this report, the applicability of the simple estimating method is investigated for SR treatment of the thick welded joint, by comparing the estimated results with the accurate ones obtained by FEM.

A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part I: Development of the Analytical Method for Relaxation Tests and Its Applicability

1996 ◽  
Vol 118 (3) ◽  
pp. 343-350 ◽  
Author(s):  
K. Nakacho ◽  
Y. Ueda
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
Welded Joint ◽  
Uniaxial Stress ◽  
Stress Relief ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Hand Calculation ◽  
Analytical Result ◽  
Good Coincidence

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In this first report, an estimating method is developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is very similar to that observed in the SR treatment of a joint. Using the various relations between stress and strains in the relaxation tests, estimating equations are formulated in order to simply calculate the change of the stress. The results obtained by applying the equations are compared with the highly accurate analytical result based on the finite element method. Both results show such a good coincidence that the appropriateness of the adopted method is confirmed. In the next report, this method is extended to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part III: Development of Estimating Equations for Multiaxial Stress State in Thick Welded Joint

2001 ◽  
Vol 124 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Keiji Nakacho
Keyword(s):  
Stress State ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Welded Joint ◽  
Estimating Equations ◽  
Stress Relief ◽  
Pressure Vessels ◽  
Relaxation Phenomenon ◽  
Multiaxial Stress ◽  
Multiaxial Stress State

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of a very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is considerably similar to that observed in the SR treatment of a joint. In the second report, the stresses relaxed by SR treatment in a very thick welded joint were analyzed accurately by the finite element method based on thermal elastic-plastic creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state were studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex. In this report, the estimating equations in multiaxial stress states are developed for the stress relaxation phenomenon in the thick welded joints, based on the foregoing characteristics.

Analysis on Fracture Morphology and Microstructure of T92 Steel after High Temperature Multiaxial Creep

2013 ◽  
Vol 860-863 ◽  
pp. 967-971
Author(s):  
Xue Ping Mao ◽  
Xiao Wang ◽  
Sai Dong Huang ◽  
Chao Li ◽  
Hong Xu ◽  
...  
Keyword(s):  
High Temperature ◽  
Stress State ◽  
Standard Specimen ◽  
Uniaxial Stress ◽  
Fracture Morphology ◽  
Multiaxial Stress ◽  
Creep Life ◽  
Creep Tests ◽  
Multiaxial Stress State ◽  
Multiaxial Creep

The high temperature creep tests of standard specimen and double U-type notch specimen of T92 steel were carried out under different stresses at 650 °C. Then optical microscopy and scanning electron microscopy were used to observe the fracture morphology and microstructure. The results show that the multiaxial stress state leads to the creep fracture cracking initiation in notch. Under multiaxial stress state, the failure mode of T92 steel is transgranular and dimple plastic fracture, and is more obvious with the increase of creep life. Compared with under uniaxial stress state, the precipitates under multiaxial stress state are larger in size and quantity, and are much coarser.

Effect of multiaxial stress state on creep damage in ASME T92 welded joint

2020 ◽  
Vol 43 (5) ◽  
pp. 907-918
Author(s):  
Xiao Wang ◽  
Xue Wang ◽  
Chuang Wang ◽  
Ya‐Lin Zhang ◽  
Qiao‐Sheng Huang
Keyword(s):  
Stress State ◽  
Welded Joint ◽  
Creep Damage ◽  
Multiaxial Stress ◽  
Multiaxial Stress State

scholarly journals Modeling and Calculating of Residual Stress and Strain of Butt Welded Joint

2021 ◽  
Vol 31 (5) ◽  
pp. 58-67
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welded Joint ◽  
The Finite Element Method ◽  
Force Method ◽  
Stress Components ◽  
Residual Stresses And Strains ◽  
Element Method

The non-uniform thermal expansion and contraction resulting from welding processes cause residual stresses and strains. Experimental studies on measuring welding residual stresses and strains of structure are costly and sometimes they are not possible. Previously, analytical methods with idealized models were developed to determine the welding residual stresses and strain. Recently, numerical methods are constructed to analyze the stresses and the strains in welded structures. This paper presents the calculation results of residual stress and welding strain in butt welded joint of S355J2G3 carbon steel of 5 mm thickness made by MAG welding process with a single pass. The calculation is performed by two methods: the imaginary force method and the finite element method. In the finite element method, the SYSWELD software is used to simulate and to determine residual stresses and strain of this welded joint. The results of finite element method are compared with those of imaginary force method to show the rationality and the advantages of finite element method. The study results have shown that in this welded joint, only the longitudinal and transverse stress components are important and the other stress components are negligible.

Thermal Sleeve Design For Pressure Vessels

1973 ◽  
Vol 2 (4) ◽  
pp. 229-234
Author(s):  
S. Venkatasubbu ◽  
P. Desrochers ◽  
C. N. Baronet
Keyword(s):  
Thin Shell ◽  
Welded Joint ◽  
Pressure Vessels ◽  
Transient Temperature ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Thermal Boundary Conditions ◽  
Pipe Radius ◽  
Maximum Stresses ◽  
Unit Pressure

The maximum stresses induced at the welded joint between a tube carrying a hot fluid and a vessel wall can be reduced by welding a thermal sleeve between them. The design stresses far various combinations of the sleeve and the tube of different mean pipe radius/thickness (R/t) ratios are presented independently for unit pressure and unit temperature of the fluid. The thermo-elastic methods used involved thick and thin shell analyses depending on the R/t ratio of the sleeve. The finite element method was used for the solution of the transient temperature and stress distributions. An experimental investigation was carried out to verify thermal boundary conditions and stress distribution.

Analysis on Fracture Mechanism of T92 Steel under High Temperature Multiaxial Creep

2014 ◽  
Vol 941-944 ◽  
pp. 1423-1427
Author(s):  
Hong Xu ◽  
Jun Yuan ◽  
Jing Liu ◽  
Sai Dong Huang ◽  
Chao Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Stress State ◽  
Uniaxial Stress ◽  
Fracture Morphology ◽  
Second Phase ◽  
Strengthening Effect ◽  
Multiaxial Stress ◽  
Creep Tests ◽  
Multiaxial Stress State ◽  
Multiaxial Creep

The high temperature creep tests of standard specimen and double U-notched specimen of T92 steel were carried out under different stresses at 600°C and 650 °C. Then scanning electron microscopy was used to observe the fracture morphology. The results show that the notch weakens plasticity, and weakening with the notch acuity. Under multiaxial stress state, the failure mode of T92 steel gradually transfers from ductile dimple to brittle quasi-cleavage fracture. Compared with uniaxial stress state, the dimples under multiaxial stress state are smaller and shallower, within lots of carbides and second phase particles. The notch slows the connection, growth and gather of microvoids, and exhibits notch strengthening effect.

The effect of differential thermal expansion on residual stresses in a welded connection

1976 ◽  
Vol 11 (1) ◽  
pp. 56-61
Author(s):  
E Procter ◽  
E M Beaney
Keyword(s):  
Residual Stress ◽  
Thermal Expansion ◽  
Residual Stresses ◽  
Welded Joint ◽  
Stress Relief ◽  
Apparent Strain ◽  
Differential Thermal Expansion ◽  
Strain Gauge Measurements ◽  
Welded Connection ◽  
Differential Expansion

Two tests were conducted on a welded joint between a forging and a pipe adaptor, to investigate the effect of differential thermal expansion in the various parts of the joint, on the residual stress. The first test was carried out with the weld in the approved manufacturing stress relieved condition. The second test was carried out following normalizing and extended stress relief heat treatments. Strain gauge measurements were made on the heat affected zones and at various positions across the weld as the forging was heated and cooled through approximately 250° C. The apparent strain outputs of the gauges used at each location were determined from gauges attached to ‘stress free islands’ machined in the weld at the required postions Since the tests could only be carried out over a 250° C range the results were linearly extrapolated to cover the range of stress relief temperatures. It is shown that differential expansion can have significant effects on residual weld stresses as the structures are temperature cycled.

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