*The Stretch Ratio "SR" and Displacement values are typically accurate, but remain approximate values.
** The Heating pull force is based on ~ 25,000 psi (172 MPa), which for many applications is the maximum safe stress for the wire. However, many applications use higher and lower stress levels. This depends on the specific conditions of a given design. The cooling deformation force is based on ~10,000 psi (70 MPa), which is a good starting point in a design. However, this value can also vary depending on how the material is used.
*** The contraction time is directly related to current input. The figures used here are only approximate since room temperatures, air currents, and heat sinking of specific devices vary. Both heating and cooling can be dramatically changed (see section 3 of the technical characteristics at http://www.dynalloy.com/TCF1140.pdf for more information.)
**** Approximate cooling time, at room temperature in static air, using a vertical spring. The last 0.5% of deformation is not used in these approximations. HT = High Temperature Flexinol® Actuator Spring.