Effect of Titanium Inclusions on HY-80 GMA Weld Deposits.

摘要

HY-80 steels are used in submarine and ship construction and it has been found that small additions of titanium to this steel during manufacture markedly improve the fracture toughness of the heat affected zone (HAZ) of Gas-Metal-Arc-Welding (GMAW) deposits made from this steel. This has been ascribed to prior austenite grain boundary pinning by titanium nitride inclusions. In the present work the weld metals, HAZ and parent metals of GMAW welds made on HY-80 steels have been studied by optical, scanning electron and transmission electron microscopy. These studies have shown that the Ti treated HY-80 has overall a lower level on non-metallic inclusions that untreated HY80 which could certainly be responsible for improved toughness. Unfortunately it proved difficult to correlate titanium nitride inclusions with prior-austenite-grain-boundary pinning.