Two-stage Heat Treatment in WAAM
A combined annealing process for homogenizing coarse-grained microstructures and relieving residual stresses in wire-based optimized components. It improves isotropic service properties.
Two-stage annealing in WAAM construction means: First, thoroughly heat the component through and hold it so that the microstructures and stresses from the welding process homogenize. Then follows the second stage, where you deliberately cool down slower or faster to set the desired mechanical properties. If you skip this or do it sloppily, hard spots and residual stresses remain, which can lead to cracks and distortion during milling or in service. The trick is that the first stage must be long enough for the entire part to reach temperature—not just the surface. And during cooling, you have to go down in a controlled manner, otherwise you'll ruin all your work again.