Abstract: Annealing process was studied in order to solve the coercivity nonconformity problem of DT4C electrical iron sleeve parts after annealing by vacuum hydrogen annealing furnace at 900 ℃. The results show that after 1120 ℃×4 h + 900 ℃×4 h two-stage annealing, the coercivity and grain size of the tested rod are significantly reduced compared with 900 ℃×4 h annealing, and the coercivity at different cooling rates during the process from 1120 ℃ to 900 ℃ is qualified and the difference is not significant. And the cooling rate reaches 240 ℃/h, the processing efficiency of the parts can be improved. The coercivity of unqualified batch sleeve parts after two-stage annealing meets the requirements of HB/Z 5015—1994.

Key words: DT4C electrical iron, coercivity, grain size, annealing, cooling rate