Effect of boron treatment on the microstructure and toughness of Ti-containing steel weld metals

Ti-containing steel weld metals with boron addition contents of 0-85 ppm were prepared, and their microstructural characteristics as well the impact toughness investigated. The results show that in these microstructures, compared to metal without boron, 22-39 a remarkable increase amount acicular ferrite at expense grain boundary ferrite, idiomorphic side-plate ferrite. However, further content up 61-85 ppm, bainitic is formed, accompanied drop In size martensite-austenite (M/A) islands much smaller, lower than those found case primarily composed during fracture specimens, crack propagation path more bent comparison large amounts or which presence improves metals. coarse readily induce micro-cracks interface between matrix, deteriorating toughness. B exhibit outstanding because high fine islands.