The effect of heat treatments and Si contents on B2 ordering reaction in high-silicon steels

The silicon content was increased up to 6.5% (by weight, unless specified o therwise) to reduce the power loss of the silicon steels. These steels were prepared by the conventional casting method or by spray forming and were i nvestigated with the aid of light optical microscopy (LOM) and transmission electron microscopy (TEM). The difference in the casting method did not re sult in any difference in suppressing the B2 ordering. The D0(3) phase was observed only in the as-cast 6.5%Si steel. It was almost impossible to supp ress the B2 ordered phase keeping the silicon level as high as 6.5% even af ter the heat treatment at 1000 degreesC for 24 h or after hot rolling. It w as necessary to change the Si level and control the cooling rate to suppres s the ordering reaction, especially, in cooling after heat treatment. The s ilicon level of 5.87% was observed to be a critical value in suppressing th e B? ordering reaction. (C) 2001 Elsevier Science B.V. All rights reserved.