Determination of Inclusion Chemistry and Size Distribution in Steel Weldments by Analytical Electron Microscopy

摘要

The U.S. Navy has been concerned about reducing the number of inclusions in steel weldments to increase the toughness of the weld metal. Research has shown that particular inclusions can nucleate the acicular ferrite micro structure in the weld metal, which can increase toughness without compromising strength. The present study investigated the inclusion chemistry and size distribution in aluminum-deoxidized C-Mn steel weldments. The results showed that the addition of aluminum to the C-Mn weld metal will produce inclusions, that can nucleate acicular ferrite by epitaxy, and that the number and volume fraction of inclusions is reduced. This indicates that aluminum deoxidation of steel weld metal can have positive benefits for C-Mn weld metal strength and toughness.