MICROSTRUCTURAL CHARACTERISATION OF AS-DEPOSITED AND REHEATED WELD METAL - HIGH STRENGTH STEEL WELD METALS

摘要

The problems encountered with the interpretation of martensite and the various forms of bainite that are found in high strength steel weld metals have been addressed. Field emission gun scanning electron microscopy was found to overcome resolution difficulties often met with light optical microscopy and conventional scanning electron microscopy. Microstructural constituents were characterised both in the as-deposited and reheated tempered states. The characterisation of retained austenite and identification of carbide types remains challenging, and transmission electron microscopy is required.