Precipitates and precipitation mechanism in non-oriented electrical steel containing copper

Precipitates in low-carbon low-silicon non-oriented electrical steel containing Cu were studied and the precipitation mechanism was analyzed by means of energy dispersive spectrometry (EDS) and selected area electron diffraction (SAED). It is found that the equiaxed precipitates of Cu with B₂-1ike structure distribute dispersively in the non-oriented electrical steel. The precipitation mechanism involves general precipitation, dislocation precipitation, interphase precipitations formed by the ledge mechanism and the bowing-out mechanism. General precipitation can occur at the three aging temperatures of 550, 650 and 750℃. Dislocation precipitation takes place only at low aging temperature (550℃), with a special form of parallel short rows. Interphase precipitation formed by the ledge mechanism is in a form of straight rows which can separate out at the above three aging temperatures, but the most appropriate temperature for precipitation is 650℃. Interphase precipitation formed by the bowing-out mechanism can occur only at high aging temperature (750℃), with a form of curve rows.