CRGO (Cold-Rolled Grain-Oriented silicon steel) and CRNGO (Cold-Rolled Non-Grain-Oriented silicon steel) are specialized steel products primarily used in electrical applications due to their superior magnetic properties. Here's a detailed comparison: 1. Definition and Basic Characteristics CRGO (Cold-Rolled Grain-Oriented silicon steel): This material undergoes a special cold-rolling and annealing process that aligns the crystalline grains in a specific direction (orientation). This orientation enhances magnetic properties in the rolling direction, making it ideal for applications where magnetic flux is primarily directional, such as transformer cores. CRNGO (Cold-Rolled Non-Grain-Oriented silicon steel): In contrast, CRNGO does not have a preferred grain orientation. Its grains are randomly oriented, resulting in isotropic magnetic properties (similar in all directions). This makes it suitable for rotating machinery like electric motors and generators, where the magnetic field changes direction. 2. Production Process Both CRGO and CRNGO are produced through a series of steps including hot rolling, cold rolling, and annealing. However, CRGO requires an additional critical step: secondary cold rolling and high-temperature annealing to develop the Goss texture (110)[001], which is responsible for its grain-oriented structure. CRNGO, on the other hand, does not undergo this texture development process, resulting in its non-oriented nature. 3. Key Applications CRGO: Its primary application is in the cores of power and distribution transformers. Its high magnetic permeability and low core loss in the rolling direction make it exceptionally efficient for minimizing energy loss in electrical transmission. CRNGO: It is predominantly used in the manufacturing of stators and rotors for electric motors​ (especially in automotive applications like electric vehicles), generators, and small transformers​ where the magnetic field is not unidirectional. Its isotropic nature ensures consistent performance regardless of the magnetic field direction. 4. Market and Industry Context The global market for these materials is significant and growing, driven largely by the expansion of the renewable energy sector and the electric vehicle (EV) industry. CRNGO demand is particularly boosted by the rapid growth in EV production, as it is a key component in efficient traction motors. China is a major producer and consumer of both CRGO and CRNGO. In 2022, China's CRNGO production was around 4.5 million tonnes, accounting for over 60% of global output. CRGO and CRNGO are essential high-performance materials in the electrical industry. The choice between them depends fundamentally on the application: CRGO is the material of choice for static equipment like transformers where magnetic fields are directional. CRNGO is indispensable for rotating machinery like motors and generators where magnetic fields are multi-directional. The growth in energy efficiency demands and the electrification of transport are key drivers for the continued innovation and market expansion of both CRGO and CRNGO

The adoption of laminated structure in transformer cores is a key design in electrical engineering, which is underpinned by profound physical principles and engineering considerations.   The challenge of eddy current loss When alternating current passes through the windings of a transformer, a changing magnetic field is generated in the core. According to the law of electromagnetic induction, this changing magnetic field will induce a circular current inside the iron core, which is called "eddy current". If a single iron core is used, these eddy currents will cause a large amount of energy to be lost in the form of heat, not only reducing efficiency but also possibly causing the iron core to overheat.   Solution for laminated structure This design can be made by stacking thin sheets of iron cores and coating each sheet with an insulating layer. 1.Significantly increase the resistance of the eddy current path 2.Limit the flow range of the vortex within a single thin sheet 3.Effectively reduce eddy current loss by over 90% Material and process optimization Modern transformers typically use silicon steel sheets with a thickness of 0.23 to 0.35mm. The addition of silicon further enhances the resistivity. The stacking direction is arranged along the magnetic field lines, which not only ensures the smoothness of the magnetic circuit but also minimizes the eddy current effect to the greatest extent.   This seemingly simple laminated design is actually the best solution to balance efficiency, cost and reliability, and remains one of the core technologies in transformer manufacturing to this day.