Magnetomechanical Applications Utilizing Silicon Iron

This paper discusses the processing and use of ironsilicon alloys [American Iron and Steel Institute (AISI) M27, M6, etc.] in electromechanical applications. These materials are more commonly used in electromagnetic applications such as transformer and motor laminations, relays, and solonoids. Resistance to mechanical stress is provided by applying hard carburized or carbonitrided cases to only those areas subjected to mechanical stress. Thus, a single part provides both magnetic softness and resistance to abrasion and impact. The process used to produce grain orientation in M6 electrical steel precludes the use of subsequent case hardening treatments. In this instance, hard inserts can provide similar resistance to impact and abrasion. The magnetic properties of these materials are of prime importance to assure functional performance. This paper describes special annealing practices which provide properties that allow maximum performance from materials of the previously mentioned types. The common industry practice of specifying magnetic properties by using core loss values is of particular interest. In electromechanical applications, these values are not sufficient to guarantee magnetic performance, therefore, properties such as maximum permeability and coercive force must be determined. This entails the selection of materials and practices that will give proper performance. The methods used in selecting suitable materials and the required testing procedures are also covered in this paper.