Heat treatment can improve the performance of metal seals. It will increase the yield strength of the material having its positive impact on seating load and spring back. The increased seating load will press the soft plating into the surface irregularities better, thereby creating a better leak tightness. The higher spring back means that the intimate contact between the seal and the mating surface is maintained longer in case of flange defl ection and flange lift-off. In some cases heat treatment can be used to improve the seal's resistance to fatigue under cyclic loads. Depending on the application HTMS offers age hardening, annealing and solution and precipitation heat treatment.

HTMS recommends heat treating all non-Spring Energised Metal C-Rings. However, heat treatment is mostly not required for Metal O-Rings and Spring Energised C-Rings. Nevertheless, some demanding applications in Oil and Gas environment do require heat treatment to prevent material embrittlement. (NACE-compliant alloy 718 / For NACE-compliant materials, other than alloy 718, please contact HTMS.)