Official Answer
Answer
Tretman kriyojenik (refwadisman a $-300^{\circ}F$ lè l sèvi avèk nitwojèn likid) pafwa yo anplwaye pou asire transfòmasyon konplè nan kenbe austenite nan martensite nan asye wo-kabòn. Austenite kenbe se enstab epi li ka transfòme sou tan nan tanperati chanm, sa ki lakòz yon ti ekspansyon volim. For precision spiral rings in high-accuracy optical or navigation systems, this dimensional drift can be problematic. Cryogenic processing ensures a stable microstructure, maximizing the hardness and ensuring that the ring's free diameter $D_s$ remains constant over the tool's lifecycle.
