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The effect of weld filler metal austenite to acicular ferrite transformation temperature on the residual stresses that arise during the gas metal arc welding of a low carbon steel has been examined using a finite element model. It was found that the stress levels in the weld can be tailored by the appropriate selection of the filler metal and compressive, near zero or tensile residual stresses produced. Reasonable agreement was obtained between the model and the stresses measured using neutron diffraction both in welds using conventional and low transformation temperature filler metal. [ABSTRACT FROM AUTHOR]

In this paper, prediction and controlling angular distortion in fillet welded joint and structure were investigated. First, two methods to reduce angular distortion in fillet welded joint were investigated by experimental and numerical analysis. One was to apply a constant external force in-process and the other was rigid clamping. In numerical analysis, a new in-house finite element code has been developed based on the idea of iterative substructure method (ISM) to calculate welding distortion in rational time. During experimental analysis, the constant external force was designed and applied in-process to reduce angular distortion of fillet welded joint. The results showed that the distortion can be efficiently predicted by ISM, which were in good agreement with the experimental ones. Applying constant external force in process was a more effective method to reduce distortion than using rigid clamping. In addition, with a constant load distance from weld bead, the locations of the applied constant external force and rigid clamping along the longitudinal direction (welding direction) have little influence on the magnitude of welding angular distortion. Finally, the angular distortion of a large fillet welded structure was predicted with ISM and also controlled with applying a constant external force based on the simulation results of the fillet welded joint. [ABSTRACT FROM AUTHOR]

Using an in house finite element (FE) code developed based on the idea of iterative substructure method (ISM), this paper presents a numerical study to evaluate the effects of welding sequence, fixture condition and prestrain on the residual welding distortion in a fillet welded structure. The results show that welding sequence has appreciable influence on residual distortion, appropriate fixture can greatly reduce angular distortion in the workpiece and application of prestrain can significantly reduce the residual distortion. Taking advantage of the high efficiency of ISM, the optimum scheme of prestrain has been numerically predicted within practical time based on a systematic investigation. [ABSTRACT FROM AUTHOR]

The finite element method is a powerful tool for predicting welding distortion. However, the mechanical phenomena are strongly non-linear and transient and thus, thermo–elastic–plastic finite element analyses of the phenomena require very long computational time. To overcome this problem, an interactive substructure method was developed as an approach to reduce the computational time in three-dimensional analyses. In this paper, in order to confirm calculation efficiency for a large scale problem, a pipe model with 538 200 degrees of freedom was computed. Furthermore, the residual distortion in an engine component was computed and the applicability of the calculation for problems in welding practices was demonstrated. [ABSTRACT FROM AUTHOR]