Welding HAZ 2D: Thermal Cycle & Zone Cross-Section

Arc welding leaves a banded landscape of microstructures behind it, and this 2D companion sim renders that banding the way a real weld-cross-section micrograph does: as a semicircular slice cut through the plate directly under the seam. Rather than reading zone temperature off the arc's closest approach the way the 3D voxel model does, this version numerically maximizes the full transient Rosenthal moving-point-source solution over the entire weld pass at every offset, so the true peak-temperature envelope — and how far behind the arc it actually lags — comes from real time-domain physics. A second panel plots the genuine thermal cycle at a probe offset you choose, tracing the heating and cooling curve live and shading the 800→500 °C window whose width is the t₈/₅ cooling time welding codes use to judge hardening and cracking risk. Adjust arc power, travel speed, preheat and material and watch both the cross-section bands and the thermal cycle respond together.