The effect of copper precipitates on the recrystallization textures and magnetic properties of non-oriented electrical steels

• Small quantities of copper were added to non-oriented electrical steels.
• A metastable Cu-rich phase precipitated in hot-rolled bands.
• The Cu-rich phase has a structure that differs from a twinned 9R or 3R.
• The copper precipitates can improve the recrystallization textures of the steels.
• The copper precipitates can also significantly reduce the core loss of the steels.

Small quantities of copper were added to non-oriented electrical steels to produce a metastable Cu-rich phase with a different structure from a twinned 9R or 3R and an average size on the order of 20 nm. These precipitates were observed in hot-rolled bands coiled at 650 °C for between 1 and 3 h. The coiling time and copper content have little effect on the average size of the precipitates, but the amount of the precipitates increases significantly with the Cu content, and the particles appear to coalesce when the copper level rises to 0.35%. The influence of the precipitates on the recrystallization textures and magnetic properties of non-oriented electrical steels was investigated, and it can be concluded that the Cu-rich precipitates can improve the recrystallization textures of soft magnetic materials by inhibiting the {1 1 1} texture component and promoting the Goss component. However, this beneficial effect is weakened when the Cu-rich particles coalesce or the coiling time is extended. Furthermore, the Cu-rich precipitates can significantly reduce the core loss of non-oriented electrical steels by improving the recrystallization textures without obviously decreasing the magnetic induction.