Abstract: Taking 2 pieces of hot rolled Fe-3%Si-Cu alloy plates as the research object, over-aged and solution-treated respectively and multi-pass cold rolled, and then recrystallization annealed at 500-800 ℃, the recrystallization behaviors of the cold rolled Fe-3%Si-Cu alloy plates were researched by studying the microstructure after annealing and the hardness change with different annealing processes. The results show that when the hot-rolled specimens are over-aged at 650 ℃, the fcc ε-Cu phase is precipitated with the morphology of ellipsoidal or rod-shaped, and the size of the rod-shaped copper-rich phase is large, with its long axis being greater than or equal to 100 nm. Both the specimens treated by different heat treatments before cold rolling show that the complete recrystallization time is shortened with the increase of annealing temperature, while due to the precipitation of copper-rich phase, the fully recrystallization time of the specimen solution-treated is significantly shorter than that of the over-aged. When the annealing temperature is 500 ℃, because the softening caused by the recovery is not enough to offset the hardening caused by precipitation, the hardness curve of the solution-treated specimen shows an obvious aging hardening peak when the annealing time is 10⁴ s. When the annealing temperature is above 600 ℃, the solution-treated specimen shows the recrystallization dominated annealing characteristics, and without aging hardening peak on the hardness curve.

Key words: Fe-3%Si-Cu alloy, copper-rich precipitate, recrystallization, hardness