Industrial robots are often called "the pearl at the crown of manufacturing." What truly determines a robot's "agile brain" and "precise muscles" is the servo motor hidden inside each joint – it controls speed, positioning, and torque, directly impacting the robot's accuracy, response speed, and service life.

In recent years, demand for humanoid and collaborative robots has exploded. China's servo motor market reached RMB 22.3 billion in 2024 and is expected to exceed RMB 28 billion by 2026. Among the core components of a servo motor, electrical steel (non-oriented electrical steel, NOES) is the key material for stator and rotor cores, and its performance directly affects motor efficiency.

So how should you select electrical steel for industrial robot motors scientifically? This article walks you through selection points, mainstream grades, and future trends, providing a clear and actionable reference for motor design engineers.

Electrical Steel – The "Soft Magnetic Foundation" of Industrial Robot Motors

What is electrical steel?

Electrical steel, also known as silicon steel, is an iron-based soft magnetic alloy containing 0.5%–4.5% silicon. Because its internal grain orientation is random and magnetic properties are isotropic, it is called non-oriented electrical steel (NOES). It features low iron loss and high magnetic flux density, making it the core material for rotating electrical machines, including servo motors.

Today, cold-rolled electrical steel has completely replaced hot-rolled products. Common thicknesses range from 0.23 to 0.50 mm, suitable for operating frequencies from 50 Hz to 1,000 Hz. Typical grades include B35A300 and B50A470.

Role of electrical steel in the supply chain

From a cost perspective, electrical steel accounts for a significant portion of raw material costs for servo motors. In 2024, China produced approximately 13.15 million tons of NOES, the largest in the world, led by major players such as BaoSteel, Angang, and Shougang. Advances in electrical steel directly drive upgrades in downstream motor products.

Four "Hard Requirements" of Industrial Robot Motors for Electrical Steel

Unlike conventional motors, servo motors are not about speed – they are about precision control and dynamic response. Therefore, the demands on electrical steel are much more stringent.

Iron Loss – The Decisive Factor for Efficiency & Heat Generation

Iron loss consists of hysteresis loss and eddy current loss. Under high‑frequency alternating magnetic fields, eddy current loss increases dramatically, which requires thinner steel laminations.

• Lower iron loss → higher           efficiency rating → lower temperature rise → longer      motor life

Permeability & Magnetic Flux Density – Determines Torque Density & Size

The higher the magnetic flux density (B value), the greater the torque output capability. High‑induction electrical steel allows for smaller and lighter cores, making robot joint motors more compact.

• Higher magnetic induction →           higher torque density → smaller robot joints

Thickness – The Critical Variable for High‑Frequency Operation

Eddy current loss is proportional to the square of the lamination thickness. As robot motors move toward higher frequency and higher speed, electrical steel thickness continues to decrease:

• Traditional: 0.50 mm

• Current mainstream: 0.35 mm, 0.20 mm

• High‑end direction: 0.10 mm ultra‑thin gauge

Grade Selection: Higher Grade Is Not Always Better

Important principle: Higher grade ≠ best choice.
A higher grade means lower iron loss, but magnetic permeability may decrease. For small precision motors, permeability is often critical.

Therefore, selection must balance power rating, operating frequency, cost constraints, and performance targets – finding the optimal trade‑off between iron loss and permeability.

Practical Application – Mainstream Electrical Steel Grades & Representative Suppliers

When selecting materials for industrial robot servo motors, the choice should match power level, operating frequency, and specific application scenarios. In general, high‑grade 0.35 mm NOES offers a good balance of performance and economy for conventional industrial robots.

In recent years, China's domestic electrical steel industry has achieved major breakthroughs.

BaoSteel: World‑first robot‑dedicated electrical steel

In 2025, BaoSteel globally launched four new high‑performance NOES products, including:

• AHR series dedicated to embodied robots – provides a domestic solution for dexterous‑hand coreless motors and frameless torque motors, breaking long‑standing import dependence.

• B10AHV900M – only 0.10 mm thick, with iron loss breaking through a long‑standing industry bottleneck, greatly improving high‑speed motor performance.

• B50AM250 – designed for IE6 ultra‑premium efficiency motors, providing core material for the world's  first IE6‑rated motor.

Baosteel's new‑energy NOES production line has an annual capacity of 550,000 tons, focusing on 0.15–0.65 mm ultra‑thin gauges, high magnetic induction, and multi‑coating products, covering more than 20 high‑end grades.

Shougang: Advancing in both EV and industrial motors

Shougang’s Zhixin facility has delivered over 20 million tons in total, building the world’s first specialized production line for electrical steel used in new‑energy vehicle drive motors. Its NOES portfolio includes four series with more than 100 products. Shougang pioneered high‑silicon (3.7% Si) high‑grade NOES and has accumulated extensive experience in EV drive motors and high‑efficiency industrial motors.

The Value of a Professional Supplier – Why Choose Shanghai Ruichao Industrial?

In the highly specialized field of electrical steel selection, choosing a reliable supplier is often more important than simply chasing the highest grade.

Shanghai Ruichao Industrial is a professional service provider deeply rooted in the electrical steel industry. We have long supplied high‑quality non‑oriented and grain‑oriented electrical steel as well as value‑added services to motor and transformer customers.

Our advantages:

• ✅ Staying ahead of  industry trends – We continuously track developments in industrial robots, new‑energy vehicles, and high‑efficiency industrial motors to optimize our product portfolio.

• ✅ Targeted selection      advice – Based on your specific application (servo motors, drive motors, precision rotating equipment, etc.), we provide customized           material solutions.

• ✅ One‑stop support – From material selection and supply chain assurance to technical consulting, we reduce your selection risk and enhance your product's core competitiveness.

Building a long‑term partnership with Shanghai Ruichao Industrial means having a professional team to support every upgrade of your motor materials.

Better Electrical Steel, Better Robots

Industrial robots are rapidly penetrating every corner of manufacturing. The performance ceiling of servo motors depends largely on the selection and application of electrical steel – a "silent champion" material.

Scientific and rational electrical steel selection not only affects motor efficiency and reliability, but also directly determines the overall competitiveness of industrial robot products. Whether you are looking at general grades such as B35A300 and B50A470, or extreme‑performance ultra‑thin grades like B10AHV900M, you need a systematic evaluation framework to achieve precise matching.

Scientific and rational electrical steel selection not only affects motor efficiency and reliability, but also directly determines the overall competitiveness of industrial robot products. Whether you are looking at general grades such as B35A300 and B50A470, or extreme‑performance ultra‑thin grades like B10AHV900M, you need a systematic evaluation framework to achieve precise matching.

With the rapid development of emerging industries such as humanoid robots and low‑altitude economy, the demand for high‑end electrical steel will continue to expand. Under the twin opportunities of domestic substitution and efficiency upgrades, Shanghai Ruichao Industrial looks forward to working with you to empower next‑generation industrial robot motors with higher‑performance electrical steel and jointly drive China's robotics industry to new heights.

For more details on electrical steel selection or to obtain professional material recommendations, please contact Shanghai Ruichao Industrial. We provide one‑stop technical service and supply chain solutions.