Detailing Microstructural Evolution Roadmap in the Weld Metal of EH420 Shipbuilding Steel Subjected to Varied Reheating Inputs

Microstructural evolution roadmap in the weld metal of EH420 shipbuilding steel subjected to various reheating inputs has been investigated. As reheating inputs increase, major microstructures transform from lath bainites, to granular bainites, to acicular ferrite, and to polygonal ferrite. Corresponding frequencies of high-angle grain boundaries increase from 30 to 57.7 pct as reheating inputs increase from 50 to 150 kJ/cm, while a changeover occurs, leading to an appreciable reduction to 45.5 pct, at 200 kJ/cm.

Automated summary

The microstructural evolution roadmap in the weld metal of EH420 shipbuilding steel under different reheating inputs has been studied. As the reheating inputs increase, the major microstructures change from lath bainites to granular bainites, then to acicular ferrite, and finally to polygonal ferrite. The frequency of high-angle grain boundaries increases from 30 to 57.7 pct as reheating inputs increase from 50 to 150 kJ/cm, but a changeover occurs at 200 kJ/cm, leading to a significant reduction to 45.5 pct.