Modelling of inertia welding of IN718 superalloy

A simple model for the inertia welding of a nickel based superalloy is proposed. The heat flow occurring in the vicinity of the joint is considered, assuming it to be one-dimensional, and this is coupled to a treatment of the stress state expected there using Hill's general method, so that the upset can be estimated. A state variable constitutive model is included, for the IN718 alloy. It is demonstrated that many of the important characteristics of the process are predicted correctly. It is shown that the shear stress developed at the last stage of the process must be accounted if the upset is to be correctly predicted. The results are compared with those from a 2 1/2D finite element model of the process, and the differences rationalised.