Why are CRGO cores used for transformers?

CRGO stands for Cold Rolled Grain Oriented steel. CRGO steel has high magnetic permeability and low core losses and hence useful for making transformers. It is made through a process of cold rolling and heat treatment which aligns grain structure of the steel. The crystal lattice is aligned with the rolling direction. That improves the magnetic permeability which is the ability to be magnetized, which is essential for efficient transformer function. CRGO steel has about 3% silicon content which also improves its magnetic properties and reduces hysteresis losses. CRGO core is made of stacked CRGO laminations. Laminations are coated with an insulating material to prevent conduction of eddy currents between them. This reduces energy dissipation as heat.