Direct Extrusion of As-cast Ti 6Al-4V Ingots into Aerospace Structural Components

Titanium alloy ingots in the as-cast condition exhibit extremely coarse grains, in the range of several millimeters to centimeters, which follow solidification patterns creating strong texture. These textured coarse grains do not permit ultrasonic inspection due to significant noise that gives rise to false positives or insufficient inspection sensitivity necessary to meet the defect detectability requirements. The as-cast structure also has poor hot workability that leads to surface defects and dimensional control issues. The standard practice to refine grain structure and breakdown texture is application of several steps of controlled thermo-mechanical working that improves inspectability and workability. However, this processing is significantly expensive and time consuming. Intermediate products such as billets are routinely inspected ultrasonically to assess whether its quality is suitable for the final processing and eventual service. A novel method of reliably inspecting titanium billets in the as-cast condition and producing aerospace structural components via direct extrusion of as-cast Ti 6Al-4V billets will be presented in this talk. The ability to ultrasonically inspect as-cast billets combined with improved hot workability permits an economical method of manufacture of titanium alloy components destined for high performance applications.