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American Society for Testing and Materials

Influence of thermo-mechanical material properties of different steel grades on welding residual stresses and angular distortion

A computationally efficient solution is adopted for 3D transient analyses of both thermal and structural responses of steel plates to single-pass gas tungsten arc welding. Considering the temperature-varying thermal and mechanical properties of the steel material, the temperature distribution in the plate calculated by the numerical approach turned out to have a good agreement with the experimental results of butt welding tests. The structural response of welded plates including the residual stress and deformation has also been studied. The numerical results generally agree well with the experimental measurements. The effect of the Element Birth–Death technique has been discussed in detail, considering the double ellipsoidal moving heat source. The magnitude of peak temperature in the plates is found 8.76 % higher when taking into account the Element Birth-Death effect. The effects of finite element mesh size and convection coefficient on the simulation result have been discussed. The convection coefficient has a very low effect on the maximum temperature but is critical to the temperature gradient in the cooling stage.

Numerical and experimental studies on temperature and distortion patterns in butt-welded plates

Distortion and residual stresses in thick plate weld joint of austenitic stainless steel: Experiments and analysis

In this paper, investigation of residual stress and distortion induced in 3 mm thick Modified 9Cr-1Mo steel plates during GTA welding is carried out. SYSWELD software is used for the thermo-mechanical analysis. A 3D meshed model is created for the simulation and double ellipsoidal heat source distribution is used for the thermal analysis. Thermal cycles predicted near the fusion zone are compared with experimentally measured thermal cycles using thermocouples. Predicted residual stress profile across the fusion zone is compared with the measured profile using X-ray diffraction method. There is a good agreement between measured and predicted thermal cycles and residual stress profile. Distortion of the weld joint is measured using vertical electronic height gauge. Finite element analysis of distortion of the weld joint is carried out by applying both large and small distortion theories. Comparison of experimental and numerical results showed better accuracy if large distortion theory is applied.

Experimental and finite element analysis of residual stress and distortion in GTA welding of modified 9Cr-1Mo steel

One major disadvantage of many arc welding processes is welding-induced residual stresses and distortions. The non-uniform heating and cooling during arc welding result in non-uniform expansion and contraction of the weld and surrounding base material, which produces undesirable residual stresses and deformations in the welded joint. A number of methods can be used to control welding-induced distortions. The methods used for controlling welding distortions a ect residual stresses and vice versa. One practical method for minimizing welding angular distortions is the use of clamping. In this paper, the e ect of clamping and clamp releasing time on welding residual stresses and distortions in the single-pass butt welding of 304 stainless steel plates are investigated. Cases with and without clamping have been studied, and residual stresses and angular distortions have been predicted by three-dimensional nite element simulation. Moreover, experiments have been carried out to measure temperature histories, angular distortions and residual stresses for the unclamped case to verify the numerical model. The results of this study revealed that clamping and clamp release time have a great in uence on the distribution of residual stresses and nal angular distortions. Using clamping during welding and releasing after cooling to ambient temperature can signi cantly reduce the amount of nal angular distortions.

Investigation of the effect of clamping on residual stresses and distortions in butt welded plates

During arc welding process, non-uniform heating and cooling lead to non-uniform expansion and contraction of the weld and surrounding base metal which result in undesirable residual stresses and distortions in the welded joint. Among different types of welding distortions, angular distortions produced by butt welding of plates are of major concern in industry. Various methods are currently being used to control and reduce angular distortions. Among different types of distortion control methods the ones which can also reduce residual stresses are preferred. In this paper, the effect of welding sequence and direction on reduction of welding-induced angular distortions in single-pass butt-welded 304 stainless plates and also their effect on residual stresses are investigated by numerical simulation. Welding simulation has been performed using a three-dimensional thermo-elastic–plastic finite element model. In order to verify the numerical model, experiments have also been carried out and temperature historie...

Mahsa Seyyedian Choobi

Papers

Investigation of the effect of clamping on residual stresses and distortions in butt welded plates

Effect of welding sequence and direction on angular distortions in butt-welded plates: