X-Ray Analysis of Residual Stress in Weld Region of X70 Pipeline Steel

2014 ◽  
Vol 936 ◽  
pp. 2011-2016 ◽  
Author(s):  
Zakaria Boumerzoug ◽  
Kelthoum Digheche ◽  
Vincent Ji
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Pipeline Steel ◽  
Welding Process ◽  
Diffraction Method ◽  
Optical Microscope ◽  
Heat Treatments ◽  
X70 Pipeline Steel ◽  
X Ray ◽  
Weld Region

X-ray diffraction method has been used to analyze the residual stress distribution in weld region of an X70 pipeline steel before and after heat treatment. The welding process has been realized by industrial arc welding with circular weld seams. The effect of heat treatments on the level and the distribution of residual stresses were investigated. Stress distribution was characterized by relative high compressive stresses in weld seam just after welding. However, residual stress relaxation phenomenon was observed in weld region after heat treatments due to microstructure restoration and recrystalization. Optical microscope observation and Vickers hardness measurements were also realized as complementary microstructure characterization techniques.

Residual Stress Evaluation of Dissimilar Weld Joint Using Reactor Vessel Outlet Nozzle Mock-Up Model (Report-1)

2008 ◽  
Author(s):  
Itaru Muroya ◽  
Youichi Iwamoto ◽  
Naoki Ogawa ◽  
Kiminobu Hojo ◽  
Kazuo Ogawa
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Welding Process ◽  
Reactor Vessel ◽  
Residual Stress Distribution ◽  
Test Model ◽  
Alloy 600 ◽  
Outlet Nozzle ◽  
Stress Evaluation ◽  
Weld Region

In recent years, the occurrence of primary water stress corrosion cracking (PWSCC) in Alloy 600 weld regions of PWR plants has increased. In order to evaluate the crack propagation of PWSCC, it is required to estimate stress distribution including residual stress and operational stress through the wall thickness of the Alloy 600 weld region. In a national project in Japan for the purpose of establishing residual stress evaluation method, two test models were produced based on a reactor vessel outlet nozzle of Japanese PWR plants. One (Test model A) was produced using the same welding process applied in Japanese PWR plants in order to measure residual stress distribution of the Alloy 132 weld region. The other (Test model B) was produced using the same fabrication process in Japanese PWR plants in order to measure stress distribution change of the Alloy 132 weld region during fabrication process such as a hydrostatic test, welding a main coolant pipe to the stainless steel safe end. For Test model A, residual stress distribution was obtained using FE analysis, and was compared with the measured stress distribution. By comparing results, it was confirmed that the FE analysis result was in good agreement with the measurement result. For mock up test model B, the stress distribution of selected fabrication processes were measured using the Deep Hole Drilling (DHD) method. From these measurement results, it was found that the stress distribution in thickness direction at the center of the Alloy 132 weld line was changed largely during welding process of the safe end to the main coolant pipe.

On Axisymmetric Residual Stresses in Tubes With Longitudinally Nonuniform Stress Distribution

1993 ◽  
Vol 60 (2) ◽  
pp. 300-309 ◽  
Author(s):  
T. Nishimura
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Diffraction Method ◽  
Residual Stress Distribution ◽  
New Method ◽  
Element Analysis ◽  
Simple Modification ◽  
X Ray

New equations for calculating residual stress distribution are derived from the theory of elasticity for tubes. The initial distribution of the stresses including the shearing stress is computed from longitudinal distributions of residual stresses measured by the X-ray methods at the surface after removal of successive concentric layers of material. For example, the residual stresses of a steel tube quenched in water were measured by the X-ray diffraction method. The new method was also applied to a short tube with hypothetical residual stress distribution. An alternative finite element analysis was made for a verification. The residual stresses computed by finite element modeling agreed well with the hypothetical residual stresses measured. This shows that good results can be expected from the new method. The equations can also be used for bars by simple modification.

Residual Stresses in Butt Welding of Two Circular Pipes: An Experimental and Numerical Investigation

2014 ◽  
Author(s):  
Gurinder Singh Brar
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Welding Process ◽  
Diffraction Method ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray

Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is carried out with a very complex thermal cycle which results in irreversible elastic-plastic deformation and residual stresses in and around fusion zone and heat affected zone (HAZ). A residual stress due to welding arises from the differential heating of the plates due to the weld heat source. Residual stresses may be an advantage or disadvantage in structural components depending on their nature and magnitude. The beneficial effect of these compressive stresses have been widely used in industry as these are believed to increase fatigue strength of the component and reduce stress corrosion cracking and brittle fracture. But due to the presence of residual stresses in and around the weld zone the strength and life of the component is also reduced. To understand the behavior of residual stresses, two 10 mm thick Fe410WC mild steel plates are butt welded using the Metal Active Gas (MAG) process. An experimental method (X-ray diffraction) and numerical analysis (finite element analysis) were then carried out to calculate the residual stress values in the welded plates. Three types of V-butt weld joint — two-pass, three-pass and four-pass were considered in this study. In multi-pass welding operation the residual stress pattern developed in the material changes with each weld pass. In X-ray diffraction method, the residual stresses were derived from the elastic strain measurements using a Young’s modulus value of 210 GPa and Poisson’s ratio of 0.3. Finite element method based, SolidWorks software was used to develop coupled thermal-mechanical three dimension finite element model. The finite element model was evaluated for the transient temperatures and residual stresses during welding. Also variations of the physical and mechanical properties of material with the temperature were taken into account. The numerical results for peak transverse residual stresses attained in the welded plates for two-pass, three-pass and four-pass welded joint were 67.7 N/mm2, 58.6 N/mm2, and 48.1 N/mm2 respectively. The peak temperature attained during welding process comes out to be 970°C for two-pass weld, 820.8°C for three-pass weld and 651.9°C for four-pass weld. It can be concluded that due to increase in the number of passes during welding process or deposition weld beads, the residual stresses and temperature distribution decrease. Also, the results obtained by finite element method agree well with those from experimental X-ray diffraction method.

Residual Stress and Microstructures Characterization in Welded Al-Si-12Cu Alloy

2013 ◽  
Vol 856 ◽  
pp. 201-204
Author(s):  
Z. Boumerzoug ◽  
Chérifa Bouremel ◽  
V. Ji
Keyword(s):  
Residual Stress ◽  
Welded Joint ◽  
Dendritic Structure ◽  
Welding Process ◽  
Diffraction Method ◽  
Hardness Measurement ◽  
Optical Microscope ◽  
Stress Evolution ◽  
X Ray Diffraction ◽  
Isothermal Heat Treatments

X-ray diffraction method has been used to analyze the residual stress distribution across the joint of Al-Si-12Cu alloy just after welding process. On the other hand, isothermal heat treatments have been applied in order to study the residual stress evolution in this material. Optical microscope observation and Vickers hardness measurement have been carried out as complementary microstructure techniques. The different zones of welded joint have been analyzed, where the fusion zone was characterized by dendritic structure and different to heat affected zone. We have found a softening phenomenon in welded joint after heat according to microhardness results.

A short-wave X-ray diffraction method to evaluate the residual stress of welding joint for 7N01 Al alloy

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940047
Author(s):  
Zhiyi Zhang ◽  
Xiaojun Xu ◽  
Zhiqing Sun ◽  
Qibin Tang ◽  
Ren Wang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Welding Process ◽  
Diffraction Method ◽  
High Energy ◽  
Short Wave ◽  
Middle Part ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray

The residual stress with different degree is inevitable to be introduced during the welding process for high strength 7N01 Al alloys, which will deteriorate the mechanical properties in service. Therefore, a proper characterization method is of vital importance to obtain the detailed residual stress distribution. The conventional X-ray diffraction method can only measure the residual stress of near surface but cannot determine the internal bulk stress with nondestructive way. In the present work, a new Short-Wave X-Ray Diffraction (SWXRD) test methodology was utilized, which can evaluate not only the surface but also the internal residual stress of a crystalline material by applying the monochromatic short-wave X-ray of high-energy. The results show that there is a “M” shaped distribution of residual stress of longitudinal direction (LD) in different affected zone. Furthermore, the characterization of residual stress along weld depth direction demonstrates that the middle part of weld joint is subjected to tensile stress while the rest is subjected to compressive stress.

Experimental Investigation on Intensity and Residual Stress in Superficial Layers Induced by Water Cavitation Peening with Aeration

2008 ◽  
Vol 373-374 ◽  
pp. 754-757 ◽  
Author(s):  
Dong Ying Ju ◽  
B. Han
Keyword(s):  
Residual Stress ◽  
Process Capability ◽  
Diffraction Method ◽  
Spring Steel ◽  
Bubble Collapse ◽  
Process Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Enhancement Method ◽  
The Impact

Water cavitation peening (WCP) with aeration is a novel surface enhancement method. A new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. In this study, in order to investigate the process capability of the WCP with aeration, a standard N-type almen strips of spring steel SAE 1070 was treated by WCP with various process conditions, and the arc height value and the residual stress in the superficial layers were measured by X-ray diffraction method. The optimal fluxes of aeration and the optimal standoff distances were achieved.

The Experimental Study of Diffraction Angle of Aluminum Alloy 3003

2012 ◽  
Vol 625 ◽  
pp. 291-296
Author(s):  
Neng Quan Duan ◽  
Jian Liang Ren ◽  
Rui Qiang Pang
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Measurement ◽  
Electrical Measuring ◽  
Diffraction Method ◽  
Measuring Method ◽  
X Ray ◽  
Equal Strength ◽  
Diffraction Angle ◽  
Stress Measuring

The most suitable diffraction angle of aluminum alloy 3003 used for stress measuring is aimed to be determined in this paper. The experiment makes a stress measurement of a loading aluminum alloy 3003 equal strength beam with the traditional electrical measuring method and the X-ray stress measurement. With the electrical measuring method as reference, the research study the measured values that acquired from the X-ray diffraction method when the diffraction angle are 142° and 156°, and then compare them with that acquired from electrical measuring method. The measurement results demonstrate that the diffraction angle at 156 ° is better than at 142 ° based on the assessment standards of the liner slope and the distribution of data. Thus the optimum diffraction angle for X-ray to measure the macroscopic stress of aluminum alloy 3003 is 156 °. In this paper，the stress caused by the load on the equal strength beam is assumed to be "residual stress" and thus the conclusion has reference values for the standardization of residual stress measurement of aluminum alloy by XRD and has theoretical guiding significance in the production practices.

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