Influence of Titanium-Containing Inoculants on the Structure of Metal in the Welds of High-Strength Low-Alloy Steels

摘要

We study the influence of titanium-containing refractory inoculants (nitrides, carbides, and intermetallic materials) on the structure of metal in the welds of high-strength low-alloy steels. The character of structural-and-phase transformations and the specific features of fine structures are determined by the method of transmission electronic microscopy with regard for the dislocation density distribution. The influence of structural components formed as a result of introduction of various types of inoculants on the mechanical properties of welded joints is investigated. The roles played by the structural factors (phase composition, subgrain structure, and the distribution of dislocations) in the behavior of local internal stresses and stress concentrators in the process of crack initiation are analyzed. For the case of welding of high-strength low-alloy steels, we determine the optimal compositions of applied inoculants guaranteeing the possibility of getting of high-quality and reliable welded joints with high mechanical characteristics and crack-growth resistance.