An optimal design of the widths of heat affect zone, fusion zone, and near interface zone in a dissimilar metal welded joint

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Guoliang Guo ◽  
Jie Yang ◽  
Lei Wang ◽  
Guiqiu Liu ◽  
Baozhong Zhang ◽  
...  
Keyword(s):  
Optimal Design ◽  
Fusion Zone ◽  
Welded Joint ◽  
Heat Affect Zone ◽  
Interface Zone ◽  
Dissimilar Metal ◽  
Zone Fusion

Effects of Stress-Relief Annealing on the Residual Stress and the Microstructure of TA15 Welded Joint

2016 ◽  
Vol 849 ◽  
pp. 281-286 ◽  
Author(s):  
Teng Ma ◽  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Song Xiao Hui ◽  
Rui Liu
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Fusion Zone ◽  
Maximum Stress ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Stress Relief ◽  
Welding Zone ◽  
Weave Structure ◽  
Effects Of Stress

The effects of stress-relief annealing on the distribution of residual stress and on the microstructure of TA15 (Ti-6.5Al-2Zr-1Mo-1V) alloy joints by electron beam welding (EBW) were investigated. The results indicated that the microstructure of welded joint presented a transitional change, i.e. basket-weave structure appeared in the fusion zone while equiaxed α structure in base metal. No significant change occurred in microstructure after annealing at 650°C for 2 h. The residual stress in fusion zone was mainly tensile stress and the maximum longitudinal stress value was 473MPa. After annealing, the residual stress near the welded joint exhibited a uniform distribution and the maximum stress droped to 150 MPa. The yield stress and tensile stress of the TA15 welding zone were 1016 MPa and 1100 MPa respectively.

Effects of Welding Wire Composition on Microstructure and Mechanical Properties of Welded Joint in Al-Mg-Si Alloy

2022 ◽  
Vol 905 ◽  
pp. 44-50
Author(s):  
Li Wang ◽  
Ya Ya Zheng ◽  
Shi Hu Hu
Keyword(s):  
Mechanical Properties ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Weld Zone ◽  
Xrd Analysis ◽  
Metallographic Analysis ◽  
Strengthening Effect ◽  
Welding Wire ◽  
Microstructure And Mechanical Properties

The effects of welding wire composition on microstructure and mechanical properties of welded joint in Al-Mg-Si alloy were studied by electrochemical test, X-ray diffraction (XRD) analysis and metallographic analysis. The results show that the weld zone is composed of coarse columnar dendrites and fine equated grains. Recrystallized grains are observed in the fusion zone, and the microstructure in the heat affected zone is coarsened by welding heat. The hardness curve of welded joint is like W-shaped, the highest hardness point appears near the fusion zone, and the lowest hardness point is in the heat affected zone. The main second phases of welded joints are: matrix α-Al, Mg2Si, AlMnSi, elemental Si and SiO2. The addition of rare earth in welding wire can refine the grain in weld zone obviously, produce fine grain strengthening effect, and improve the electrochemical performance of weld.

Cause Analysis and Preventive Measures against Cracks in 15Cr1Mo1V Steel Welded Joint in Service

2017 ◽  
Vol 863 ◽  
pp. 328-333
Author(s):  
Wei Shi ◽  
Yi Shi Lv ◽  
Zhong Bing Chen ◽  
Ling Hui Meng ◽  
Li Jun Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stress Concentration ◽  
Welded Joint ◽  
Welding Process ◽  
Postweld Heat Treatment ◽  
Additional Stress ◽  
Heat Affect Zone ◽  
Crack Morphology ◽  
Deformation Ability ◽  
Postweld Heat

Characteristics and forming causes of the cracks in welded joint of 15Cr1Mo1V steel serviced 70000h are investigated by mechanical and chemical testing and crack morphology observation. Results show that the cracks initiate from welded metal or coarse grain heat affect zone (CGHAZ) near fusion line, and there are three kinds of defects observed in the crack region, which are macrocracks, microcracks and voids. According to the forming position, process and morphology of the cracks, it is estimated that the cracks are a kind of stress relief crack (SRC). The main reasons of the cracking are because of residual stress caused by improper temperature field during post welding heat treatment, strong stress concentration caused by welding structure, additional stress caused by abnormal hangers & supports and decreased ductility of welded joint in service. The SRC in welded joint can be avoided through optimizing the welding process and postweld heat treatment(PWHT) process to ensure enough critical ductility deformation ability εc and avoiding and reducing stress concentration and additional stress to decrease ductility deformation εP of welded joint which make εc>εp consistently.

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