Advancements in Interface Layer Design for Ti and Steel Welding: A Review

The connection between dissimilar materials, Ti and steel, has been a focal point for global scholars. Establishing a high-strength bond between Ti alloy and stainless steel offers the potential to harness their respective advantages and reduce production costs, holding significant applications and far-reaching implications. Currently, non-transition welding methods for Ti/steel, primarily diffusion welding and vacuum brazing, have been pivotal in the early stages of development. Despite their simplicity and convenience, effectively avoiding the formation of brittle Ti–iron compounds in the weld seam, these methods face challenges such as unwelded defects, posing a risk to the reliability of welded structures under service conditions. This limitation restricts their application in products requiring high reliability. The evolving transition welding process, progressing from a single metal interface layer to a multi-metal interface layer, addresses some of the shortcomings of traditional Ti and steel connections, offering promising application prospects. This article delves into the core issue of selecting interface-layer elements and welding methods. Through an analysis of the metallurgical properties of transition metals in conjunction with Ti and steel, the study investigates the impact of single- or bimetallic elements, such as Cu, V, Nb, and Ni, on preparing interface-layer transition metals. A comprehensive review of existing research on Ti and steel welding is presented, with an emphasis on the metallurgical characteristics of their connection. The influence of element selection and welding processes on the metallurgical features and relevant mechanical properties of the weld metal is systematically analyzed and summarized.