INTRODUCTION: Manufacturing components made from superelastic alloys require understanding and careful control of the thermo-mechanical properties of the design. The proper Time-Temperature-Transformation (TTT) diagram is essential to making the final design and process successful. However, these diagrams are frequently only used in the early design stages of a product design and are less applicable after manufacturing processes have modified a device’s Af temperature. OBJECTIVE: In this case study, a TTT diagram is generated for a specific NiTi component that was subjected to a complex manufacturing process. METHODS: Cut, but not processed, NiTi tubing intended for medical device manufacture was heat treated at different times and temperatures. A molten salt pot and room temperature water were used to heat and quench each sample. A method based on ASTM F2082-01 was used to measure the active Austenite finish (Af) temperature of each sample before and after heat-treating. The method was modified to accommodate the small samples of material. RESULTS: The resulting Af temperature was plotted against the heat treating time and temperature inputs to generate the TTT diagram. This diagram was produced with NiTi material from one manufacturer and compared to a second TTT diagram produced with a second vendor’s material. CONCLUSIONS: The TTT diagram is useful for the raw material selection, to finalize design, material selection and manufacturing processes of a device and to check incoming and outgoing material. The results of this study also will help determine if the TTT diagram is device design and/or vendor specific.