Strengthen of Mechanism of 30CrMnSiNi2A Steel Welded Joint with Ultrasonic Impact Treatment

2014 ◽  
Vol 599-601 ◽  
pp. 103-106
Author(s):  
Zhan Ming Li ◽  
You Li Zhu ◽  
Xiao Kun Du
Keyword(s):  
Compressive Stress ◽  
Fusion Zone ◽  
Welded Joint ◽  
Diffraction Method ◽  
Strengthening Mechanism ◽  
Residual Compressive Stress ◽  
Ultrasonic Impact Treatment ◽  
Hardness Tester ◽  
Coarse Dendrite ◽  
Welding Defects

To analyze the strengthening mechanism of 30CrMnSiNi2A steel welded joint with ultrasonic impact treatment (UIT), the welded joint specimens were full coverage strengthened by the technology. The microstructure of the surface layer in fusion zone of the welded joint with and without UIT was investigated by optical microscopy (OM). The hardness and residual stress distributions along the thickness direction were also measured by micro-hardness tester and X-ray diffraction method respectively. The results show that the microstructure in fusion zone of the untreated 30CrMnSiNi2A steel welded joint were coarse dendrite, and there were many welding defects in this zone. UIT has the ability to achieve more compact microstructure with only small welding defects. The average hardness value of the treated specimens reached 571 HV, increased 14.4% as compared with that of the untreated specimen (499 HV). A residual compressive stress layer with thickness of 850 μm was also obtained from by UIT, and the maximum residual compressive stress was-347 MPa. The grain refinement, work hardening and residual compressive stress in fusion zone introduced by UIT increased its anti-fatigue performance.

Numerical simulation of the effect of ultrasonic impact treatment on welding residual stress

2021 ◽  
pp. 2150175
Author(s):  
Tao Mo ◽  
Jingqing Chen ◽  
Pengju Zhang ◽  
Wenqian Bai ◽  
Xiao Mu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Compressive Stress ◽  
Welded Joints ◽  
Welding Process ◽  
Residual Compressive Stress ◽  
Welding Residual Stress ◽  
304 Stainless Steel ◽  
Residual Tensile Stress ◽  
Ultrasonic Impact Treatment

Ultrasonic impact treatment (UIT) is an effective method that has been widely applied in welding structure to improve the fatigue properties of materials. It combines mechanical impact and ultrasonic vibration to produce plastic deformation on the weld joints surface, which introduces beneficial compressive residual stress distribution. To evaluate the effect of UIT technology on alleviating the residual stress of welded joints, a novel numerical analysis method based on the inherent strain theory is proposed to simulate the stress superposition of welding and subsequent UIT process of 304 stainless steel. Meanwhile, the experiment according to the process was carried out to verify the simulation of residual stress values before and after UIT. By the results, optimization of UIT application could effectively reduce the residual stress concentration after welding process. Residual tensile stress of welded joints after UIT is transformed into residual compressive stress. UIT formed a residual compressive stress layer with a thickness of about 0.13 mm on the plate. The numerical simulation results are consistent with the experimental results. The work in this paper could provide theoretical basis and technical support for the reasonable evaluation of the ultrasonic impact on residual stress elimination and mechanical properties improvement of welded joints.

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.

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.

Effect of Laser Shock Peening on the Structure and Prosperity of K403 Alloy

2014 ◽  
Vol 670-671 ◽  
pp. 52-55
Author(s):  
Yan Chai ◽  
Wei Feng He ◽  
Guang Yu He ◽  
Yu Qin Li
Keyword(s):  
Surface Roughness ◽  
Grain Boundary ◽  
Compressive Stress ◽  
Residual Compressive Stress ◽  
Laser Shock Peening ◽  
Test Results ◽  
Laser Shock ◽  
Surface Microhardness ◽  
Shock Region ◽  
Shock Peening

To solve the crack and fracture problem in blade made of K403 alloy, the samples of K403 are laser shock processed and then the microstructure, microhardness, residual compressive stress and surface roughness of the samples are tested. The test results show that some grains are observed refined in the grain boundary of shock region, the microhardness improves in a depth of 0.8mm from the surface and the surface microhardness improves 16%, a residual compressive stress which is more than 450MPa is developed in a depth of 1mm from the surface, and obvious changes of the surface roughness are not tested.

Effect of 7050 Aluminium Alloy Microstructure on Residual Stress by Laser Shock Processing

2012 ◽  
Vol 463-464 ◽  
pp. 1363-1367
Author(s):  
M.L. Zhang ◽  
J.M. Wang ◽  
Y.F. Jiang ◽  
Q.L. Zhang ◽  
Q.L. Zhou
Keyword(s):  
Residual Stress ◽  
Aluminium Alloy ◽  
Compressive Stress ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Residual Compressive Stress ◽  
Original Structure ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Shock Processing

The solution treatment and solution and aging treatment (T6) were disposed on 7050 aluminium alloy, then local processed by laser shock processing (LSP) with high-rate neodymium glass laser. The microhardness and residual stress on the surface of 7050 aluminium alloy were tested, then how the microstructure influences the residual stress on the surface of 7050 aluminium alloy by laser shock processing was analysed. The results show that the microhardness and residual compressive stress on the surface of 7050 aluminium alloy treated by solution and aging treatment was higher, and decreased obviously treated by solution treatment; the microhardness and residual compressive stress on the surface of 7050 aluminium alloy increased obviously by solution treatment and solution and aging treatment after laser shock processing; treated by solution treatment and solution and aging treatment, the microhardness and residual compressive stress of the material with uniform original structure was higher than the material with nonuniform original structure.

Study on Microstructure and Property of the SHS Welding Joint

2012 ◽  
Vol 590 ◽  
pp. 51-55
Author(s):  
Hui Yang ◽  
Guo Dong Zhang ◽  
Yuan Mei Fei
Keyword(s):  
Base Metal ◽  
Large Scale ◽  
Welded Joint ◽  
Automatic Measurement ◽  
Weld Interface ◽  
Hardness Tester ◽  
Metallurgical Bonding ◽  
Structure Morphology ◽  
Digital Microscope ◽  
Welding Metal

With the self-designed welding powder formula,this experiment employed the SHS reaction to weld the base metal,which was steel Q235 here,then respectively used Olympus large-scale horizontal digital microscope to analyze the structure morphology of the welding seam's different regions,JEOL SEM to point-analyze and line-analyze elements' distribution near the the weld interface and HV-1000 CCD automatic measurement microscopic vickers hardness tester to measure the microhardness of the pure copper's welding seam.The experiment's result shows the hardness of different part of the welded joint varies largely,and that the join of alloy elements can increase the microhardness of the welding metal,and that the welding metal and base metal interdiffuse,grow and mix remarkably near the fusion line,realizing wonderful metallurgical bonding.

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