How to Make CRNGO Steel Stator Core？

author: Zove

2026-01-09

How to Make CRNGO Steel Stator Core: A Complete Guide

Introduction to CRNGO Steel
Key Properties and Advantages
Manufacturing Process Step-by-Step
CRNGO vs. CRGO: Critical Comparison
Typical Parameters and Specifications
Expert Insights and Recommendations
Industry FAQs
Conclusion

1. Introduction to CRNGO Steel

CRNGO (Cold Rolled Non-Grain Oriented) steel is a specialized electrical steel specifically engineered for rotating electrical machines like motors and generators. Unlike its counterpart CRGO (Cold Rolled Grain Oriented) steel, which has a preferred magnetic direction, CRNGO exhibits isotropic magnetic properties. This means it performs almost equally well when magnetized in any direction across the plane of the sheet, making it the ideal material for stator and rotor cores where the magnetic flux path is complex and multi-directional.

The production of a high-performance stator core begins with selecting the right grade of CRNGO steel, followed by precision manufacturing processes to minimize energy losses and maximize efficiency.

2. Key Properties and Advantages of CRNGO Steel

CRNGO steel is defined by several critical characteristics that make it indispensable for stator cores:

Isotropic Magnetic Behavior: Provides consistent performance regardless of the rolling direction, crucial for the circular design of stators.
Low Core Losses: Formulated with silicon (typically 0.5%-3.5%), it reduces eddy current losses and hysteresis losses, enhancing motor efficiency.
High Magnetic Permeability: Allows for easier establishment of magnetic flux, improving the motor's power density.
Good Mechanical Strength: The cold-rolling process and alloying provide sufficient rigidity for punching and stacking processes.
Surface Insulation: Often comes with an insulating coating (C-4, C-5, C-6) that reduces inter-laminar eddy currents.

3. Manufacturing Process Step-by-Step

Creating a stator core from CRNGO steel is a multi-stage precision operation.

H3: 3.1. Material Selection and Inspection

The process starts with choosing the correct CRNGO grade (e.g., M250-35A, M400-50A) based on the target motor's frequency, power, and efficiency requirements. The sheet thickness, commonly 0.35mm, 0.50mm, or 0.65mm, is selected to balance core loss and manufacturability.

H3: 3.2. Precision Stamping/Blanketing

CRNGO coils are fed into a progressive die stamping press or a high-speed blanketing line. The die precisely cuts out the stator lamination shape, including the outer contour, inner bore, slots, and notches. For ultra-thin, high-performance applications, as discussed in our previous blog How to make 0.2mm stator core?, laser cutting or fine-blanking might be employed for even greater precision and minimal deformation.

H3: 3.3. Deburring and Cleaning

The stamped laminations undergo deburring to remove sharp edges (burrs). Excessive burrs can create short circuits between layers, increasing eddy current loss. The laminations are then cleaned to remove contaminants.

H3: 3.4. Stacking and Bonding

The individual laminations are stacked to the required core length. They are aligned using dowels or notches. The stack is then bonded using:

Interlocking: Small tabs are stamped and bent to hold layers.
Welding: Spot welding at specific points.
Adhesive Bonding: Applying epoxy between layers.
Riveting: Using through-rivets.

H3: 3.5. Insulation and Final Assembly

The final core stack may receive a secondary insulation treatment. It is then ready for assembly into the motor housing, followed by the insertion of copper windings into the slots.

4. CRNGO vs. CRGO: Critical Comparison

Feature	CRNGO Steel (Non-Grain Oriented)	CRGO Steel (Grain Oriented)
Grain Structure	Random, isotropic grains.	Highly aligned, anisotropic grains in the rolling direction.
Magnetic Property	Excellent in all directions in the sheet plane.	Exceptional in the rolling direction, poor in others.
Typical Core Loss	Higher than CRGO for equivalent thickness.	Lower in the rolling direction.
Primary Application	Stator & Rotor Cores (Motors, Generators).	Transformer Cores (where flux is unidirectional).
Cost	Generally lower.	Higher due to complex processing.
Formability	Good, easier to stamp complex shapes.	More brittle, challenging for complex shapes.

Why CRNGO Wins for Stators: The magnetic flux in a stator core rotates and changes direction constantly. CRNGO's isotropic nature ensures uniform magnetic performance throughout this rotating field, whereas CRGO would suffer poor performance in directions away from its grain orientation.

5. Typical CRNGO Stator Core Parameters

The following table outlines general specifications for commonly used CRNGO steel in stator cores. Exact values depend on the manufacturer and specific grade.

Parameter	Typical Value / Range	Notes
Standard Thickness	0.35mm, 0.50mm, 0.65mm	Thinner laminations (e.g., 0.2mm) reduce eddy current loss.
Core Loss (P1.5/50)	2.0 W/kg to 6.0 W/kg	Loss at 1.5 Tesla & 50 Hz. Lower is better for efficiency.
Magnetic Induction (B50)	1.60 T to 1.75 T	Flux density at 5000 A/m. Higher allows for compact design.
Silicon Content	0.5% - 3.5%	Reduces core loss and increases resistivity.
Surface Coating	C-4, C-5, C-6	Organic or inorganic insulation to reduce interlaminar loss.
Standard Width	Up to 1300 mm	From coiled stock.

6. Expert Insights and Recommendations

Dr. Emma Lin, Senior Materials Engineer at ElectroSteel Tech, shares her view:

"The biggest mistake in CRNGO stator core manufacturing is compromising on lamination quality for short-term cost savings. Poor stamping leads to burr formation, which creates localized shorts and hotspots. For high-efficiency motors (IE4/IE5), investing in precision tooling, proper annealing after stamping to relieve stress, and using thin-gauge, high-silicon grades is non-negotiable. The focus must be on minimizing total core loss, not just the material cost per kilogram."

Her recommendations align with the advanced techniques we explored for How to make 0.2mm stator core?, where precision and material handling are paramount.

7. Industry FAQs (Frequently Asked Questions)

Q1: Can I use CRGO instead of CRNGO for a stator core to get higher efficiency?
A: Generally, no. While CRGO has lower loss in one direction, its highly anisotropic property is detrimental in a stator where flux rotates. The poor performance in other directions will outweigh the benefit, leading to higher total loss and potential overheating. CRNGO is specifically designed for this application.

Q2: What is the main factor affecting the core loss of a CRNGO stator?
A: Core loss (Iron Loss) has two components: hysteresis loss and eddy current loss. Key factors are:

Material Grade: Higher silicon content reduces loss.
Lamination Thickness: Thinner sheets drastically reduce eddy current loss.
Manufacturing Quality: Stress from stamping and burrs can significantly increase hysteresis loss. Stress relief annealing can help.

Q3: Is a thicker insulating coating on CRNGO steel always better?
A: Not necessarily. A thicker coating provides better interlaminar resistance, reducing eddy currents. However, it reduces the stacking factor (the ratio of pure steel to total volume), effectively reducing the cross-sectional area for magnetic flux. An optimal balance must be found based on operating frequency.

Q4: How does the choice between 0.35mm and 0.50mm CRNGO impact motor design?
A: 0.35mm laminations have lower eddy current loss, crucial for high-frequency or high-efficiency motors. However, they are more expensive and can be slightly harder to handle. 0.50mm laminations offer a good balance of cost, mechanical rigidity, and performance for many standard industrial motor applications.

8. Conclusion

Manufacturing a high-quality CRNGO Steel Stator Core is a sophisticated process that hinges on selecting the correct material grade and executing precision-controlled manufacturing steps. Understanding its isotropic advantages over CRGO is fundamental for motor design. By focusing on minimizing core loss through superior materials like thin-gauge high-silicon CRNGO and impeccable stamping and stacking techniques—as seen in advanced practices for making 0.2mm cores—manufacturers can produce stator cores that are at the heart of more efficient, reliable, and powerful electric motors for the future.