Optimization of production process of Mg tubes produced with laser dieless drawing method and related microstructural analysis

This contribution deals with a laser dieless drawing method in which tubes (AZ31 magnesium alloy) with small dimensions are produced from previously extruded tubes with a larger diameter. The process involves local laser heating of a tube with concurrent drawing and rotation of a sample. The control parameters need to be optimized in order to get a good quality tube with low damage and regular diameter. Here, a previously developed finite element (FE) model is used for the numerical optimization. The optimization itself is multi-objective, maximizing the uniformity of the resulting tube but concurrently, minimizing its critical deformation. Since one run of the FE code lasts for several days, an approximation by a Radial Basis Function meta-model (surrogate) is used. Results reveal that there is only a very limited number of combinations of parameters leading to a uniformly shaped tubes. Finally, tubes produced with optimized parameters are analyzed from the microstructural point of view.