Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels

• Magnetic properties of a set of electrical steels were measured.
• Crystallographic texture, chemistry and grain size were studied for their effects on core loss and permeability.
• Structure–magnetic property relationships were identified for the electrical steels.

Non-oriented electrical steel (NOES) is one of the most common material used in electrical motors. Core loss and permeability are the most important properties that the motor manufacturers look for. Both these properties are structure sensitive and depend on several metallurgical factors; such as chemistry, grain size, crystallographic texture, cleanliness and stress states in non-oriented electrical steels. It has been observed in this course of the study that the grain size and Si content of NOES are the primary controlling factors to core loss, especially at higher frequencies. On the contrary, crystallographic texture plays an important role at lower frequencies. At higher frequency, core loss increases with increasing grain size and decreasing Si content of the steels. Small difference in grain size (~50 μm) at lower frequency range has little influence on the magnetic properties but has significant adverse effect as frequency reaches high enough.