A Method for Evaluation of Low Cycle Fatigue Performance of Welded Joints Based on the Properties of Welded Microzones
A welding joint, low cycle fatigue technology, applied in welding equipment, auxiliary welding equipment, welding/cutting auxiliary equipment, etc., can solve the problem of inability to accurately evaluate the low cycle fatigue performance of welded joints
Active Publication Date: 2022-03-08
XI AN JIAOTONG UNIV
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[0003] The purpose of the present invention is to provide a method for evaluating the low-cycle fatigue performance of welded joints based on the performance of welded micro-zones to solve the problem that nominal strain cannot accurately evaluate the low-cycle fatigue performance of welded joints
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Embodiment 1
[0052] The low-cycle fatigue performance evaluation process of welded joints in this embodiment is as follows: figure 1 shown. The test material is the welded joint of forged Co3W2 martensitic heat-resistant steel, the base metal is Co3W2, and the welding material is ERNiCr-1 electrode. The welded joint adopts double U-shaped grooves with a groove angle of 30°. The welding method is tungsten inert gas shielded welding for priming and manual arc welding for filling. The macroscopic appearance of the welded joint is as follows figure 2 shown. exist figure 2 The shown martensitic heat-resistant steel welded joints were sampled from the filler weld and machined into conventional bar specimens. figure 2 The box in the figure represents the gauge length section of the low cycle fatigue conventional bar sample, the gauge length section of the welded seam sample only has the weld material, and the gauge section of the welded joint sample includes the weld seam, the heat affecte...
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Abstract
A method for evaluating the low-cycle fatigue performance of welded joints based on the performance of welded micro-zones. The finite element model is established for the gauge length section of the bar-shaped sample, and the finite element model is divided into different micro-zones, and each micro-zone is endowed with elastic properties and plastic properties. Apply a displacement load to the finite element model, calculate the local strain distribution of the gauge length section under different nominal strains, calculate the local strain in the plastic zone under different nominal strains according to the local strain distribution, and use the elastic-plastic finite element method to endow each micro-area with elastic-plastic mechanical properties Calculated local strains in the plastic zone to evaluate the low cycle fatigue performance of welded joints. After using the local strain in the plastic zone instead of the nominal strain to evaluate the low-cycle fatigue performance of the welded joints, in 10 2 ~10 5 Within the low cycle fatigue life range of cycles, the maximum difference between the low cycle fatigue life measured by the welded joint sample and the low cycle fatigue life measured by the welded seam sample at the same strain level is reduced from 5.1 times to 1.3 times.
Description
technical field [0001] The invention belongs to the technical field of mechanical engineering welding, and in particular relates to a method for evaluating the low-cycle fatigue performance of a welded joint based on the performance of welding micro-zones. Background technique [0002] Welded structures are widely used in large equipment, pressure vessels, railway transportation, navigation and aerospace, petrochemical and other fields, and continuous dynamic load conditions are more common in their working environments. The current low-cycle fatigue performance evaluation method of welded joints usually regards the welded joint as a homogeneous material, and uses the nominal strain measured by the extensometer as the control parameter of the low-cycle fatigue test of the welded joint and the evaluation parameter of the low-cycle fatigue performance. This method does not take into account the inhomogeneity of micro-area properties of welded joints. However, the material pro...
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IPC IPC(8): G01N3/32
CPCB23K37/02
Inventor 张建勋徐甄真朱波
Owner XI AN JIAOTONG UNIV