Formation and Thermodynamic Analyses of Inclusions in Ti-Containing Steel Weld Metals with Different Al Contents

DIFFERENT Al CONTENTSTi-containing steel weld metals with Al contents of 0.01-0.085%were prepared.The effects of Al contents on the inclusions evolution were investigated by means of thermodynamic calculations coupled with electron probe micro-analyses and transmission electron microscopy.The results show that the inclusions in the 0.01% Al weld metal are mainly composed of ilmenite with some amounts of (Mn-Si-Al)-oxide and titanial_spinel.When Al content is increased up to 0.035%, a more amount of corundum and a small amount of pseudobrookite are formed.In 0.085% Al weld metal, the (Mn-Si-Al)-oxide disappears completely, and the inclusions contain a substantial amount of corundum, in addition to a minimal amount of pseudobrookite.Ti 3 O 5 , MnTi 2 O 4 and MnTiO 3 are the primary constituents of pseudobrookite, titanial_spinel and ilmenite, respectively.Titanial_spinel and ilmenite have higher amounts of Mn, but lower Ti levels compared with pseudobrookite.In the case of presence of a considerable amounts of titanial_spinel and ilmenite, Mn-depleted zone is formed in matrix around the inclusions.