# EFFECTS OF LOW-TEMPERATURE HEAT TREATMENT ON ELASTIC MEMORY PROCESS OF COLD WORKED STAINLESS STEEL WIRE

• 오정세 (부산대학교 치과대학 교정학교실) ;
• 박수병 (부산대학교 치과대학 교정학교실) ;
• 손우성 (부산대학교 치과대학 교정학교실)
• Oh, Jeung-Sei (Dept. of Orthodontics, College of Dentistry, Pusan National University) ;
• Park, Soo-Byung (Dept. of Orthodontics, College of Dentistry, Pusan National University) ;
• Son, Woo-Sung (Dept. of Orthodontics, College of Dentistry, Pusan National University)
• 발행 : 1992.09.01

#### 초록

The purpose of this study was to evaluate the elastic memory process in cold worked stainless steel wire and the effect of heat treatment on it. 0.018 inch round and $0.019\times0.025$ inch rectangular wire (ORMCO stainless wire) were used in this study. Each wire type had 4 groups: non-heat treatment group, furnace heat treatment group, electric current heat treatment group, and bending after heat treatment group. Each group was consisted of 10 specimens. With the Jig, each wire was bent into v-shape uniformly, and width of two free ends of each v-shaped wire was measured by caliper (to the point of 0.1 mm correctly) at time interval of offjig, after heat treatment, 1, 2, 3, 4 hours, 1, 2, 3, 4, 5, 6 days, 1, 2, 3, 4 weeks after. The results were as follows: 1. In non-heat treatment group and bending after heat treatment group, elastic memory process was occured $60\%$ within 1 hour, and more than $90\%$ within 1 week. 2. In furnace and electric current heat treatment group, almost all elastic memory process was occured during teat treatment, and then specimen was stabilized dimensionally. 3. Magnitude of deformation by elastic memory was greater in heat treatment group than non heat treatment group and bending after heat treatment group. 4. There was no remarkable difference in deformation pattern between 0.018 inch round wire and $0.019\times0.025$ inch rectangular wire.