Numerical and experimental analysis of microstructure evolution during arc welding in armor plate steels

A modeling approach is presented for assessing microstructure evolution in the solid state after arc welding armor steel plates. Reliability of the proposed approach is appraised using the case study methodology; predictions of microstructure and hardness for as-welded samples of a specific alloy are compared with results of in-depth quantitative microstructure characterization and microhardness measurements. The experimental work was carried out on MIL A46100 armor steel plates welded with AWS E11018M covered electrodes. The modeling approach is implemented in a modular algorithm consisting of diverse tasks, each one of them based on methods described in full in literature. The original contribution of the present work consists the proposed hypothesis that at each point of the weldment the microstructure established at peak temperature during thermal cycles can be (i) assumed to be the same which corresponds to the local equilibrium condition as dictated by thermodynamics, when peak temperature is above AC1 temperature, or (ii) assumed to be the one corresponding to non-equilibrium martensite decomposition during annealing, when peak temperature is below AC1 temperature. The most important applications of the algorithm presented are debated.