Yes, Tritan plastic can be joined with ultrasonic welding. Ultrasonic welding is commonly used to join various types of thermoplastics, including Tritan, by applying high-frequency vibrations to the plastic parts to create heat, which melts and fuses the parts together. However, the specific welding parameters may vary based on the geometry, material thickness, and joint design of the parts being welded. It is recommended to perform some testing and optimization to determine the ideal welding parameters for a particular application.