Correlation of local strain with microstructures around fusion zone of a Cr-Ni-Mo-V steel welded joint

2017 ◽  
Vol 685 ◽  
pp. 205-212 ◽  
Author(s):  
De-Qiang Wang ◽  
Ming-Liang Zhu ◽  
Fu-Zhen Xuan
Keyword(s):  
Fusion Zone ◽  
Welded Joint ◽  
Local Strain

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.

Microstructure and Properties of Mg/Al Dissimilar Joints by GTAW with Al-Si Filler Wire

2014 ◽  
Vol 941-944 ◽  
pp. 2035-2038
Author(s):  
Hong Yan Du ◽  
Ya Jiang Li ◽  
Juan Wang
Keyword(s):  
Fusion Zone ◽  
Welded Joint ◽  
Weld Zone ◽  
Dissimilar Materials ◽  
High Hardness ◽  
Optical Microscope ◽  
Columnar Structure ◽  
Test Results ◽  
Dissimilar Joints ◽  
Brittle Phase

Mg/Al dissimilar materials were welded successfully by GTAW with SAlSi welding wire of Al-Si system. The nice surface forming and free defects of joints are formed. Mg/Al welded joint were tested and analyzed by means of optical microscope, scanning electron microscope, microhardness tester. The test results show that in the fusion zone of Mg side, it shows the intense columnar crystalline structure and little intergranular precipitates, and has more dendritic intergranular precipitates. However, the weld zone shows the typical columnar structure zone. There is no high hardness brittle phase in fusion zone of Mg side. The hardness of weld zone is slightly higher than one of Mg substrate, and far less than the Al substrate.

Effects of Ultrasonic Impact Treatment on the Residual Stress and Microstructure of TA15 Welded Joint

2017 ◽  
Vol 898 ◽  
pp. 1056-1062 ◽  
Author(s):  
Guang Lu Qian ◽  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Rong Chen ◽  
Teng Ma ◽  
...  
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Fusion Zone ◽  
Maximum Stress ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Maximum Tensile Stress ◽  
Residual Stress Distribution ◽  
Longitudinal Stress ◽  
Ultrasonic Impact Treatment

The effects of ultrasonic impact treatment (UIT) 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 demonstrated that a marked microstructure change occurred after welding and the microstructure of welded joint presented a transitional change, i.e. martensite appeared in the fusion zone while equiaxed α in base mental. The residual stress in fusion zone was mainly tensile stress, and the maximum longitudinal stress value was 817MPa, which located in the centerline of welded joint. The results indicated that different impact methods have different influence on residual stress distribution. After employing UIT on welding toe, the residual stress near the welded joint exhibited a uniform distribution and the maximum tensile stress dropped to-153MPa. While after applying UIT on full coverage, the curve of the residual stress was steep and the maximum stress was still tensile stress. After UIT, no significant change occurred in microstructure and the tensile strength has a little change.

Fatigue Crack Initiation Mechanism of Aluminium Alloy Welded Joint in Gigacycle Fatigue

2013 ◽  
Vol 376 ◽  
pp. 177-180
Author(s):  
Chao He ◽  
Shi Ming Cui ◽  
Yan Zeng Wu ◽  
Ze Fu Luo ◽  
Qing Yuan Wang
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Aluminium Alloy ◽  
Fusion Zone ◽  
Base Metal ◽  
Welded Joint ◽  
Fatigue Crack Initiation ◽  
Fatigue Properties ◽  
Initiation Mechanism ◽  
Ultrasonic Fatigue

Ultrasonic fatigue test was performed on 5052 aluminium alloy welded joint to investigate the very high cycle fatigue properties and the fatigue crack initiation mechanisms with the help of microhardness tester and scanning electron microscope (SEM). The results showed that the hardness of fusion zone was higher that base metal and heat affected zone, which led to the embrittlement of welded zone. Fusion zone became the weakest part of welded joint under cyclical loading. Fatigue crack usually initiated from the pores beneath the surface from the SEM observation of fracture surface. The influence of pores on the fatigue crack initiation was analyzed to figure out the deterioration of fatigue strength for welded joint as compared with base metal.

Mechanical Properties of Forged Ti-6Al-4V Structure by Electron Beam Welding

2012 ◽  
Vol 455-456 ◽  
pp. 308-313
Author(s):  
Hong Yu Qi ◽  
Jian Xie ◽  
Shao Lin Li ◽  
Xiao Guang Yang
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Fusion Zone ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Base Material ◽  
Structure Design ◽  
Large Gradient ◽  
Welded Structure ◽  
Aero Engine

The blisk (bladed disk) is a new structural component of the modern aero-engine and plays an important role in improving its performance. Ti-6Al-4V alloy joints welded by electron beam have been widely used for compressor blisk in advanced aero engine. It is necessary to analyze microstructure and mechanical properties of Ti-6Al-4V welded structure by electron beam welding (EBW) for failure analysis and structure design of blisk. Microstructure of Ti-6Al-4V welded structure by EBW was investigated by microscopic observation and micro indentation testing. Experiment results show grain coarsening in fusion zone (FZ) and heat affected zone (HAZ) appears large gradient organization structure, which presents significant local heterogeneity. On the centerline perpendicular to the welding direction, Vickers microhardness was measured in increments of 1mm, 0.5mm, 0.25mm and 0.1mm. Due to the presence of martensite, microhardness of the fusion zone is about 20% higher than that of the base material. The size of joints in different regions was acquired, 2.5 to 3.0-mm-wide in FZ and about 0.7-mm-wide in HAZ respectively. Three different types of EBW samples were designed for tensile test, including welded structure, welded joint and base material. Three different stress-strain curves of specimens were acquired, including welded joint. The experiment data indicates that the tensile strength of welded joints is 8% more than that of the base metal.

scholarly journals High-Power Fiber Laser Welding of High-Strength AA7075-T6 Aluminum Alloy Welds for Mechanical Properties Research

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7498
Author(s):  
Abdel-Monem El-Batahgy ◽  
Olga Klimova-Korsmik ◽  
Aleksandr Akhmetov ◽  
Gleb Turichin
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Fiber Laser ◽  
Fusion Zone ◽  
High Power ◽  
Heat Input ◽  
Welded Joint ◽  
High Strength ◽  
Residual Tensile Stress ◽  
Fiber Laser Welding

The results disclosed that both the microstructure and mechanical properties of AA7075-T6 laser welds are considerably influenced by the heat input. In comparison with high heat input (arc welding), a smaller weld fusion zone with a finer dendrite arm spacing, limited loss of alloying elements, less intergranular segregation, and reduced residual tensile stress was obtained using low heat input. This resulted in a lower tendency of porosity and hot cracking, which improved the welded metal’s soundness. Subsequently, higher hardness as well as higher tensile strength for the welded joint was obtained with lower heat input. A welded joint with better mechanical properties and less mechanical discrepancy is important for better productivity. The implemented high-power fiber laser has enabled the production of a low heat input welded joint using a high welding speed, which is of considerable importance for minimizing not only the fusion zone size but also the deterioration of its properties. In other words, high-power fiber laser welding is a viable solution for recovering the mechanical properties of the high-strength AA 7075-T6 welds. These results are encouraging to build upon for further improvement of the mechanical properties to be comparable with the base metal.

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