Non-oriented electrical steel sheet composition control

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Solution Overview

Problem

Non-oriented electrical steel sheets used in eco-friendly vehicle motors require high magnetic permeability, low high-frequency iron loss, and high magnetic flux density, which existing technologies fail to achieve effectively due to inadequate control of segregation elements like Sn, Sb, and P, and trace elements such as Ga and Ge.

Innovation Solution

A non-oriented electrical steel sheet is developed by simultaneously controlling the content of Ga, Ge, Sn, Sb, and P, within specific weight percentages, and optimizing the composition of Si, Al, and Mn, to enhance magnetic properties and texture, achieved through a manufacturing process involving hot rolling, cold rolling, and annealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrical steel sheets are used without controlling segregation elements (Sn, Sb, P) and trace elements (Ga, Ge), then manufacturing is simpler, but magnetic permeability is insufficient and high-frequency iron loss is high

Engineering Contradiction:
Improvemagnetic permeabilityVSAvoidcomposition control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the chemical composition parameters of the steel sheet, specifically limiting segregation elements (Sn: 0.003-0.05%, Sb: 0.003-0.03%, P: 0.003-0.05%) and trace elements (Ga: 0.0005-0.02%, Ge: 0.0005-0.02%). This systematic parameter control transforms the steel sheet's magnetic properties, achieving high magnetic permeability (≥8000 at 100 A/m) and low coercive force (≤40 A/m at B=2.0 T), thereby resolving the contradiction between improved magnetic reliability and composition control complexity.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If conventional electrical steel sheets are used without element control, then manufacturing cost is lower, but high-frequency iron loss increases

Engineering Contradiction:
Improvehigh-frequency iron lossVSAvoidmanufacturing process complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements parameter changes by optimizing the chemical composition to achieve low high-frequency iron loss. By controlling segregation elements (Sn, Sb, P) and trace elements (Ga, Ge) within specific ranges, the steel sheet achieves reduced core loss at high frequencies, which is critical for motor efficiency. The manufacturing process complexity is managed through standardized hot rolling, cold rolling, and annealing procedures that are compatible with the compositional constraints.

Inventive Principle:
Principle #35Parameter changes

3Power

If electrical steel sheet requires high magnetic flux density for low-speed torque, then magnetic properties must be optimized, but this conflicts with low high-frequency iron loss requirement for high-speed operation

Engineering Contradiction:
Improvemagnetic flux densityVSAvoidhigh-frequency iron loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent resolves this contradiction through comprehensive parameter changes in chemical composition. By simultaneously optimizing segregation elements (Sn, Sb, P) and trace elements (Ga, Ge) within specific concentration ranges, the steel sheet achieves dual optimization: high magnetic flux density (Bs≥1.85 T) for low-speed torque production and low high-frequency iron loss for high-speed efficiency. This compositional parameter control enables the motor to maintain excellent performance across the entire operating speed range.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If trace elements (Ga, Ge) and segregation elements (Sn, Sb, P) are not controlled, then manufacturing is easier, but texture control and magnetic properties deteriorate

Engineering Contradiction:
Improvetexture control precisionVSAvoidelement content control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by establishing precise control ranges for trace elements (Ga: 0.0005-0.02%, Ge: 0.0005-0.02%) and segregation elements (Sn: 0.003-0.05%, Sb: 0.003-0.03%, P: 0.003-0.05%). This systematic parameter control directly influences the steel sheet's texture development during hot rolling and annealing, achieving the required texture precision (P200/(P211+P310)≥0.5) while managing element content control through standardized manufacturing procedures.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting steel sheet exhibits improved magnetic permeability, reduced high-frequency iron loss, and increased magnetic flux density, making it suitable for high-speed rotation and contributing to extended mileage in eco-friendly vehicles.

Implementation Method 1

a method for manufacturing the non-oriented electrical steel sheet includes: producing a slab; hot-rolling the slab; cold-rolling the hot-rolled sheet; and annealing the cold-rolled sheet

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentUS11634786B2Non-oriented electrical steel sheet and method for preparing same
Publication Date: 2023.04.25 POHANG IRON & STEEL CO LTD

AI summary

A non-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes, by weight, Si: 2.0 to 3.5%, Al: 0.3 to 2.5%, Mn: 0.3 to 3.5%, Sn: 0.0030 to 0.2%, Sb: 0.0030 to 0.15%, P: 0.0040 to 0.18%, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and a remainder including Fe and unavoidable impurities, and satisfies Equation 1 below.0.05≤([Sn]+[Sb])/[P]≤25  [Equation 1]([Sn], [Sb], and [P] respectively represent the content (% by weight) of Sn, Sb, and P.)