Adams, Matthew
Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Master of Science In Mechanical Engineering.
THESIS ABSTRACT:
Incremental sheet forming (ISF) was invented to make sheet metal manufacturing more flexible, enabling rapid prototyping. However, it was initially plagued with inaccurate tolerances. With the advent of double-sided incremental forming (DSIF) more accurate sheet metal parts are capable and thus has received more interest from industry in recent years. In this thesis, the effects of both temperature control, using a vortex tube with compressed shop air, and deformation path, utilizing a reverse, reforming sequence, have on the strain induced ?-austenite to a’-martensite phase transformation in stainless steel 304L (SS304L) during double sided incremental forming were studied on a pyramidal geometry. The results show that reducing the temperature of the SS304L during deformation increases the achievable a’-martensite volume fraction (MVF), which corroborates past research findings. The study also demonstrates that implementing the reforming process increases the MVF, achieving ~90% transformation along the entire formed wall when the temperature is reduced. The ability to manipulate the ?-austenite to a’-martensite transformation from <10% to ~90% by controlling these two parameters demonstrates the ability to tailor the final material properties during incremental forming for the given application.