Effect of weld travel speed on solidification cracking behavior. Part 1: weld metal characteristics

Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade's long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence.