パイプの円周溶接のモデル化に関する検討

抄録

In the present work, a three-dimensional numerical model for circumferential GTA welding of pipes is developed. It consists of a heat conduction model and a molten pool balance model.
In the heat conduction model, the transient temperature distribution and the molten pool size have been numerically analyzed by using a finite difference method and enthalpy method in order to take the influence of latent heat into account. In the molten pool model, using the molten pool size derived from the heat conduction model, the transient theoretical configuration of molten pool is calculated, considering of the balance of gravity and surface tension. The model is classified into the following two models. One is the rotational pipe model and another is the fixed pipe model.
The influence of material properties and pipe dimensions on welding process has been discussed on the basis of numerical analysis. As a result, it is made clear that the molten pool in fixed pipe welding is more sensitive to a burn-through than the pool in rotaional pipe welding.