Difference Between Non-oriented Silicon Steel and Oriented Silicon Steel

Silicon steel, also known as electrical steel or lamination steel, is a kind of steel with a special organizational structure and magnetic properties used in the production of electrical equipment. It usually has two forms: non-oriented silicon steel and oriented silicon steel. Each variant possesses unique properties that cater to specific needs within the electrical domain. So what is the difference between non-oriented silicon steel and oriented silicon steel? This article aims to provide a comprehensive understanding of both, highlighting their definitions and explaining the key differences between the two.

Non-oriented vs. Oriented Silicon Steel: What are Differences between Them?

Though both seem similar, there exist many differences between them in terms of definition, production process, silicon content, performance, application, color, cost, etc. Let’s see them one by one.

1. Definition

Non-oriented silicon steel, also called non-grain-oriented silicon steel (NGO), is a type of electrical steel that lacks controlled grain orientation and has very low carbon content.

On the contrary, oriented silicon steel, also known as grain-oriented electrical steel, is a type of magnetic material that is highly organized and has a preferred direction of magnetic alignment. Besides, oriented silicon steel can also be subdivided into ordinary oriented silicon steel (CGO) and high magnetic induction oriented silicon steel (Hi-B) two categories. High magnetic induction oriented silicon steel is a single-orientation steel strip, mainly used to manufacture various types of choke coils, transformers, and other electromagnetic components in electronic instruments.

2. Silicon Content

Although both are cold rolled silicon steels, their silicon content is different. The silicon content of oriented silicon steel is higher than that of non-oriented silicon steel.

3. Manufacturing Process

In one word, non-oriented silicon steel has relatively lower production process requirements than oriented silicon steel.

The production process of non-oriented silicon steel is following these steps:

Pre-desulfurization of molten iron, secondary desulfurization by adding Ca0+CaF flux or rare earth elements and calcium during converter blowing. The boiling molten steel is decarburized by vacuum treatment and then further desulfurized. Ferrosilicon with low titanium and zirconium content is selected for alloying.

However, oriented silicon steel is smelted in an oxygen converter. The billet undergoes hot rolling, normalization, cold rolling, intermediate annealing, and secondary cold rolling to the finished thickness, and then undergoes decarburization annealing and high-temperature annealing. It is finally coated with an insulating layer.​

4. Grain Structure

The grains of oriented silicon steel are arranged in an orderly manner, while the grains of non-oriented silicon steel are arranged in a disordered manner.

5. Performance

Compared with non-oriented silicon steel, oriented silicon steel has lower iron loss, stronger directional magnetic properties, superior high magnetic permeability, and low loss characteristics in its rolling direction.

6. Application

Due to their different performance characteristics, there are also differences between their uses.

Oriented silicon steel is primarily utilized in high-efficiency transformers, magnetic amplifiers, and large power distribution systems where core losses need to be minimized. The directional nature of it ensures that the magnetic flux flows efficiently, increasing the overall efficiency of these electrical devices.

Conversely, non-oriented silicon steel finds its applications in electric motors, generators, and smaller transformers, where the magnetic flux direction changes frequently, and magnetic isotropy becomes advantageous.

7. Color

Through naked-eye observation, we can find that:

The color of oriented silicon steel is off-white whereas non-oriented silicon steel is metallic in color.

Useful tips: how to distinguish oriented silicon steel and non-oriented silicon steel?

There are two ways for your reference.

1. Eye Observation: their colors are obviously different. You can tell them directly with the naked eye.

2. Hand Folding: take a small piece of silicon steel and fold it twice with your hands. If it sheds off-white slag or breaks, it is oriented silicon steel. Non-oriented silicon steel is difficult to break.

8. Magnetism

One of the key differences between oriented and non-oriented silicon steel lies in their magnetic properties. Oriented silicon steel usually has higher magnetic permeability and lower core loss than non-oriented silicon steel due to its controlled grain orientation. This means that oriented silicon steel is more efficient at converting electrical energy into mechanical energy, which is essential in high-efficiency transformers and other high-performance electrical equipment.

9. Cost

In terms of cost and availability, non-oriented silicon steel is generally more affordable and easier to obtain than oriented silicon steel. The production process for the former is less complex, making it a cost-effective choice for various electrical applications. However, when efficiency and performance are critical, the latter will become a preferred option, despite its higher cost and limited availability.

In conclusion

In conclusion, both oriented and non-oriented silicon steel play indispensable roles in the electrical engineering realm. Although both are made of silicon steel, they differ in their definition, silicon content, properties, manufacturing process, applications, grain structure, color, cost, etc. But each type offers its distinct advantages, enabling engineers to select the most suitable variant for their specific application requirements, and striking a balance between performance, cost, and efficiency. I hope this article can be helpful. If you have any questions, feel free to contact us at any time.