scholarly journals Comparison of Measured Residual Stress Distributions in Extra-Thick Butt Welds Joined by One-Pass EGW and Multipass FCAW

2014 ◽  
Vol 6 ◽  
pp. 861247 ◽  
Author(s):  
Jeong-Ung Park ◽  
GyuBaek An ◽  
Wan Chuck Woo ◽  
Jae-hyouk Choi ◽  
Ninshu Ma
Keyword(s):  
Residual Stress ◽  
Arc Welding ◽  
Electron Gas ◽  
Diffraction Method ◽  
Stress Distributions ◽  
Flux Cored Arc Welding ◽  
Longitudinal Residual Stress ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Neutron Diffraction Method

This study is to measure the welding residual stress distributions in a 70 mm-thick butt weld by one-pass electron gas welding using both the inherent strain method and neutron diffraction method, respectively. Based on the measurement results, the characteristics of residual stress distribution through thickness were compared between one-pass electron gas welding and multipass flux-cored arc welding. Residual stresses in the specimens of electron gas welding measured by the inherent strain method and neutron diffraction method were well matched. The longitudinal residual stress in the multi-pass flux-cored arc welding is tensile through all thicknesses in the welding fusion zone. Meanwhile, longitudinal residual stress in electron gas welding is tensile on both surfaces and compressive at the inside of the plate. The magnitude of residual stresses due to electron gas welding is lower than that due to flux-cored arc welding.

Residual Stress Evaluation of Ni Based Weld Metal Using Neutron Diffraction Method

2006 ◽  
Vol 524-525 ◽  
pp. 697-702 ◽  
Author(s):  
Shinobu Okido ◽  
Hiroshi Suzuki ◽  
K. Saito
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Neutron Diffraction ◽  
Weld Metal ◽  
Diffraction Method ◽  
Fem Analysis ◽  
Butt Weld ◽  
Stress Evaluation ◽  
Neutron Diffraction Method

Residual stress generated in Type-316 austenitic stainless steel butt-weld jointed by Inconel-182 was measured using a neutron diffraction method and compared with values calculated using FEM analysis. The measured values of Type-316 austenitic stainless steel as base material agreed well with the calculated ones. The diffraction had high intensity and a sharp profile in the base metal. However, it was difficult to measure the residual stress at the weld metal due to very weak diffraction intensities. This phenomenon was caused by the texture in the weld material generated during the weld procedure. As a result, this texture induced an inaccurate evaluation of the residual stress. Procedures for residual stress evaluation to solve this textured material problem are discussed in this paper. As a method for stress evaluation, the measured strains obtained from a different diffraction plane with strong intensity were modified with the ratio of the individual elastic constant. The values of residual stress obtained using this method were almost the same as those of the standard method using Hooke’s law. Also, these residual stress values agreed roughly with those from the FEM analysis. This evaluation method is effective for measured samples with a strong texture like Ni-based weld metal.

Research on Deformation Prediction Method of Laser Melting Deposited Large-Sized Parts Based on Inherent Strain Method

2021 ◽  
Vol 871 ◽  
pp. 65-72
Author(s):  
Cheng Hong Duan ◽  
Xian Kun Cao ◽  
Ming Huang Zhao ◽  
Xiang Peng Luo
Keyword(s):  
Residual Stress ◽  
Laser Energy ◽  
Layer By Layer ◽  
Laser Melting ◽  
Forming Process ◽  
Deformation Prediction ◽  
Metal Parts ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

In the process of metal parts fabricated by Laser Melting Deposition (LMD), a high temperature gradient will generate due to the instantaneous high laser energy input, which will cause residual stress in the formed part of metal parts, the residual stress will result in defects like warping deformation or even cracking. In this paper, a finite element method based on inherent strain method is proposed to predict the deformation of metal parts fabricated by LMD. Firstly, combing with the birth and death element technology, a local model is established to simulate the layer-by-layer deposition in the LMD forming process, and the values of inherent strain is obtained. Secondly, the obtained inherent strain values is applied to large-sized part layer by layer, and the final deformation of large-sized part is calculated. Based on the proposed method, the efficiency of deformation prediction of large-sized metal parts fabricated by LMD could be effectively improved.

Fatigue Life Variance Prediction Incorporating Residual Stress Scatter Induced by Super-Finishing Grinding Process

2009 ◽  
Vol 416 ◽  
pp. 45-50
Author(s):  
Guang Hui Lu ◽  
Xue Ping Zhang ◽  
Er Wei Gao
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Diffraction Method ◽  
Machining Process ◽  
Stress Distributions ◽  
X Ray Diffraction ◽  
Machining Processes ◽  
Surface Residual Stress ◽  
Bearing Rings ◽  
The Impact

It is well known that there is a lager deviation in the fatigue life of machined components even under nominally identical loading conditions. Understanding and controlling fatigue life variance are essential to enhance reliability. However, few research focus on the impact of machining processes on the fatigue life variance of machined components. In this study, surface residual stress distributions of bearing rings randomly selected from a production line by super-finishing grinding, are measured by X-ray diffraction method in cutting and feed direction, and its scatter is analyzed by statistical tools. Based on the variance prediction theories, build a simplified fatigue life variance prediction model incorporating the resultant residual stresses scatter induced by machining process. Based on the Basquin equation, the model is validated by experimental data published in literature. The predicted fatigue life agrees well with the experimental average fatigue life. Statistical analysis shows that the predicted variances of fatigue life are equal to those estimated from experimental fatigue life.

Investigation of the residual stress in UO2-Mo composites via a neutron diffraction method

2020 ◽  
Vol 46 (10) ◽  
pp. 15889-15896 ◽  
Author(s):  
Liang Cheng ◽  
Rui Gao ◽  
Biaojie Yan ◽  
Changsheng Zhang ◽  
Ruiwen Li ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Diffraction Method ◽  
Neutron Diffraction Method

scholarly journals Study of Residual Stresses and Microstructural Changes in Charpy Test Specimens Reconstituted by Various Welding Techniques

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 632 ◽  
Author(s):  
Gizo Bokuchava ◽  
Peter Petrov
Keyword(s):  
Residual Stress ◽  
Laser Beam Welding ◽  
Diffraction Method ◽  
Charpy Impact ◽  
Stress Distributions ◽  
Charpy Test ◽  
Microstructural Changes ◽  
Surveillance Specimens ◽  
Weld Seams ◽  
Reactor Pressure

Changes in the reactor pressure vessel (RPV) material properties due to neutron irradiation are monitored by means of surveillance specimen programs, which are used for realistic evaluation of the RPVs’ lifetime. Due to a limited number of surveillance specimens, the evaluation of reconstitution methods by various welding techniques after Charpy impact tests is of great importance. Time-of-flight (TOF) neutron diffraction method was used to determine the residual stress distributions and microstructural changes in Charpy specimens welded by arc stud, electron, and laser beam welding techniques. The lowest level of the residual stress in weld seams regions was found for the specimen welded by electron beam with optimal parameters as compared to other techniques. At the same time, this specimen exhibits the maximal level of microstrain, which points to high dislocation density in the material. The corresponding contributions to the yield strength due to various strengthening mechanisms were estimated.

scholarly journals The Effect of Welding-Pass Grouping on the Prediction Accuracy of Residual Stress in Multipass Butt Welding

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Jeongung Park ◽  
Gyubaek An ◽  
Sunghoon Kim
Keyword(s):  
Residual Stress ◽  
Diffraction Method ◽  
Fe Analysis ◽  
Computer Memory ◽  
Butt Weld ◽  
Butt Welding ◽  
Welded Structure ◽  
Welding Sequence ◽  
Grouping Method ◽  
Neutron Diffraction Method

The residual stress analysis of a thick welded structure requires a lot of time and computer memory, which are different from those in thin welded structure analysis. This study investigated the effect of residual stress due to welding-pass grouping as a way to reduce the analysis time in multipass thick butt welding joint. For this purpose, the parametric analysis which changes the number of grouping passes was conducted in the multipass butt weld of a structure with a thickness of 25 mm and 70 mm. In addition, the residual stress by thermal elastoplastic FE analysis is compared with the results by the neutron diffraction method for verifying the reliability of the FE analysis. The welding sequence is considered in order to predict the residual stress more accurately when using welding-pass grouping method. The results of the welding-pass grouping model and half model occurred between the results of the left/right of the full model. If the total number of welding-pass grouping is less than half of that of welding pass, a large difference with real residual stress is found. Therefore, the total number of the welding-pass grouping should not be reduced to more than half.

Sign in / Sign up

Export Citation Format

Share Document