Metallographic Techniques for Microstructural Characterization of SMAW Filler Metal for HSLA 100 Steel

摘要

To understand the nature of improvements in the mechanical properties of multiple-pass, high strength steel welds, it is necessary to accurately characterize the microstructures. Most studies have characterized top bead microstructures using one of several classification schemes. In this work, a tint etchant based on sodium metabisulfite is used to enhance specific microstructural features in SMA welds with as-deposited compositions ranging from 2.0 to 3.0 weight percent nickel and 1.0 to 1.5 weight percent manganese. Additionally, these welds contained 0.5 weight percent molybdenum, and 240 to 400 ppm titanium. Through a combination of etchants and etching procedures, using both optical and electron microscopy, the microstructures of these weldments were accurately characterized allowing for the correlation of mechanical properties to asdeposited microstructures.