Bounds of the explosive weld region

1993 ◽  
Vol 29 (1) ◽  
pp. 89-93
Author(s):  
Yu. I. Fadeenko
Keyword(s):  
Weld Region ◽  
Explosive Weld

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.

A Study on the Residual Stress and Fracture Behavior of Pipeline Girth Welds Joining Pipes of Different Strength

2010 ◽  
Author(s):  
Woo-sik Kim ◽  
Jong-hyun Baek ◽  
Choel-man Kim ◽  
Young-pyo Kim
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Material Property ◽  
Fracture Behavior ◽  
Residual Stress Distribution ◽  
Element Analysis ◽  
Weld Region ◽  
Similar Materials ◽  
Base Strength ◽  
Girth Welds

The following cases of girth welded region between pipelines having different base strength were considered. The pipeline shows different fracture behavior from girth welded pipeline between similar materials due to strength mismatch and residual stress distribution. Investigation about the residual stress distribution and fracture behavior of pipeline having girth welds of the differnet base metals (X70/X65 and X70/X42) with different material property has performed using finite element analysis. The effect of mismatched material property on girth weld region is negligible when shape of pipeline is similar. The assessment for occurance of crack on girth weld region with pipes with material property mismatched can be replaced by that of the similar pipes with low strength on the point view of conservation.

New method to enhance the mechanical characteristics of Al-5052 alloy weldment produced by tungsten inert gas

2020 ◽  
pp. 095440542092977 ◽  
Author(s):  
Mahmoud Abbasi ◽  
Mohammad Givi ◽  
Behrouz Bagheri
Keyword(s):  
Friction Stir Processing ◽  
Good Alternative ◽  
Inert Gas ◽  
Tungsten Inert Gas Welding ◽  
Friction Stir ◽  
Weld Region ◽  
Workpiece Vibration ◽  
Novel Processing ◽  
Weld Area ◽  
Strength And Ductility

Tungsten inert gas welding method is widely used to weld aluminum alloys. However, the development of some defects such as porosity and undercutting which form during tungsten inert gas welding may decrease the quality of the weld. Processing of the joint by friction stir processing is a method to enhance weld quality. In the current work, the weld area produced by tungsten inert gas is processed by friction stir processing as well as a novel processing method entitled “friction stir vibration processing.” In friction stir vibration processing, the specimen is vibrated while friction stir processing is carried out. The results show that both processing methods lead to grain refinement in the weld region and increase the strength and ductility of the tungsten inert gas–welded specimen. The stir zone grain sizes of friction stir vibration–processed samples are less than those of friction stir–processed ones. It is believed that workpiece vibration in friction stir vibration processing increases the material straining and intensifies the dynamic recrystallization. By application of friction stir processing on tungsten inert gas–welded specimen, ultimate tensile strength and ductility increase by about 10% and 22%, respectively. They increase by about 17% and 33%, respectively, as friction stir vibration processing is applied. The results also indicate that the effect of friction stir vibration processing on the microstructure of the weld region and its mechanical properties increases as vibration frequency increases. Friction stir vibration processing is a good alternative for friction stir processing, and it is recommended for application in industry.

Study on Welding of TIG Tailor Welded Galvanized Sheets and Formability of Stretch Forming

2011 ◽  
Vol 704-705 ◽  
pp. 1512-1518
Author(s):  
Yun Tao Li ◽  
Wen Jun Zhang ◽  
Xu Ma ◽  
Guang Da Liu ◽  
Li Jun Yang
Keyword(s):  
Fracture Surface ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Tensile Axis ◽  
Weld Line ◽  
Tig Welding ◽  
Stretch Forming ◽  
Weld Region

In this study TIG welding of Tailor welded Galvanized Sheets and their formability of stretch forming have been carried out. It has been found that the microstructure of weld region is ferrites and pearlites, and the microstructure of heat-affected zone (HAZ) is blocky pearlites and ferrites. Stretch tests suggested that when the weld line parallels the tensile axis, σs , σb and the σs/σb is higher than that of the weld line perpendicular to the tensile axis. When the weld line parallels the tensile axis, the elongation of the specimen and n are lower than that of the specimen with the weld line perpendicular to the tensile axis. When the weld line perpendicular to the tensile axis, the fracture surface is basically the same as that of the base metal, when the weld line parallels the tensile axis, the fracture surface is dimples and cleavages.

scholarly journals Evaluation of Weld Homogenization Schemes Based on Plastic Loading of Single Edge Notched Tension (SE(T)) Tests

2017 ◽  
Author(s):  
Sameera Naib ◽  
Wim De Waele ◽  
Stijn Hertelé
Keyword(s):  
Base Metal ◽  
Structural Integrity ◽  
Structural Response ◽  
Tensile Tests ◽  
Critical Assessment ◽  
Analysis Procedure ◽  
Single Edge ◽  
Weld Region ◽  
Weld Defect ◽  
Plastic Analysis

Engineering Critical Assessment (ECA) of welds is the process of predicting the structural integrity of a structure in the presence of a weld defect under specified loading conditions. Standardized ECA techniques consider the weld to be equal in properties when compared with base metal or use the concept of ‘strength mismatch’ to distinguish the weld from the base metal. In both cases, the weld region is homogeneous. This is a severe approximation from reality, as welds show complex strength heterogeneity patterns. The authors are concerned with techniques to simplify welds in such way that the structural response of the weld is similar to that of the idealized, homogeneous weld. Two approaches are considered: (a) integrating properties along assumed slip lines originating from the defect tip, and (b) assigning All Weld Metal Tensile Tests (AWMTT) to the entire weld region. A plastic analysis procedure suggested by the ASME BP&V code (‘Twice Elastic Slope method’) is adopted to estimate Plastic Load, whose values are compared for the heterogeneous and equivalent homogeneous welds. Finite Element (FE) simulations were performed for Single Edge notched Tensile (SE(T)) specimens. The results put forward the possibilities of weld homogenization while showing its limitations. This will assist in further improvement of weld ECA.

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