Automotive Bushing Steel Bar Purity Through ECOARC Refining

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Solution Overview

Problem

Existing methods for producing steel bars for automotive bushings do not adequately meet the high mechanical property, high hardness, and high purity requirements necessary for high-end applications, particularly in terms of wear resistance, tensile strength, temperature resistance, and corrosion resistance, which are crucial for ensuring the safety and performance of transmission devices in automobiles.

Innovation Solution

A method involving ecological and economical arc furnace (ECOARC) smelting, LF refining, RH refining, continuous casting, and rolling processes is employed, utilizing specific chemical compositions and process parameters to produce steel bars with optimized mechanical properties and high purity, including steps such as alloy addition, slag smelting, diffusion deoxygenation, and controlled argon pressure during refining, followed by heating, rolling, and heat treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional steel production methods are used, then production cost and simplicity are maintained, but mechanical properties, hardness, and purity do not meet high-end automotive requirements

Engineering Contradiction:
Improvemechanical propertiesVSAvoidproduction process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The production process is divided into multiple discrete refining stages (LF refining, RH refining, vacuum degassing) where each stage targets specific impurities or compositional requirements. This segmentation allows systematic achievement of high purity and controlled mechanical properties through incremental processing rather than a single complex operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Alloying elements are added and preliminary refining operations are performed during the smelting and refining stages before the final casting. This preliminary preparation ensures the steel composition and purity are optimized in advance, enabling the final product to meet high-end automotive requirements without requiring complex post-processing.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If high purity and high mechanical properties are achieved through multiple refining stages, then steel quality is improved, but production time and process complexity increase

Engineering Contradiction:
Improvesteel purityVSAvoidproduction cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The refining process maintains continuous useful action through sequential operations (LF refining followed by RH refining with vacuum degassing) where each stage builds upon the previous one without significant idle time. The process continuously removes impurities and optimizes composition, achieving high purity efficiently through uninterrupted processing rather than intermittent operations.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The process utilizes parameter changes in temperature, pressure, and atmospheric conditions across different refining stages to optimize impurity removal. By dynamically adjusting these parameters (e.g., temperature control during LF refining, vacuum pressure during RH refining), the process achieves high purity efficiently without excessive time consumption.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If strict quality requirements for automotive bushings are implemented, then product reliability is improved, but manufacturing complexity and process control difficulty increase

Engineering Contradiction:
Improveproduct qualityVSAvoidprocess control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The refining process incorporates feedback mechanisms where steel composition and purity are monitored at each stage, and processing parameters are adjusted accordingly. This feedback control ensures consistent achievement of target quality specifications while managing process complexity through data-driven decision-making rather than rigid fixed procedures.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Precise control of processing parameters (temperature, pressure, alloying amounts) is implemented to ensure consistent product quality. By establishing optimal parameter ranges and maintaining them throughout the refining process, the system achieves reliable high-quality steel without requiring overly complex control systems.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If ECOARC smelting with 100% scrap steel is used, then ecological and economical benefits are achieved, but control of chemical composition precision becomes more difficult

Engineering Contradiction:
Improveecological and economical efficiencyVSAvoidchemical composition control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Preliminary alloying adjustments are made during the ECOARC smelting process itself, with calculated amounts of alloying elements added to compensate for variations in scrap steel composition. This preliminary action establishes a foundation for achieving target chemical composition, which is then refined further in subsequent stages.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The process utilizes parameter changes in the smelting conditions (temperature, oxygen potential, alloying rates) to control the chemical composition outcome. By dynamically adjusting these parameters during ECOARC smelting, precise compositional control is achieved despite the variability inherent in using 100% scrap steel.

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 method produces steel bars with enhanced mechanical properties, high hardness, and high purity, ensuring good surface quality and impact performance, meeting the stringent requirements of high-end automotive bushings for improved safety and performance.

Implementation Method 1

ecological and economical arc furnace (ECOARC) smelting

Methodology Applied
Scientific EffectArc heating: Electric Arc

Implementation Method 2

uses 100% (in percentage by mass) scrap steel as raw materials for smelting, with a loading amount of the scrap steel of 116-122 t and a tapping temperature of 1655-1665° C.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

LF refining adopts a high current of 20000-25000 A to heat for slag smelting

Methodology Applied
Scientific EffectElectric arc heating: Electric Arc

Implementation Method 4

heat for slag smelting

Methodology Applied
Scientific EffectSlag smelting: Oxidation

Implementation Method 5

RH refining

Methodology Applied
Scientific EffectVacuum degassing: Vacuum

Implementation Method 6

when a vacuum degree of a vacuum chamber reaches 100-110 Pa, timing begins for 10-15 min, while the argon pressure is adjusted to 0.3-0.5 MPa for calm argon blowing

Methodology Applied
Scientific EffectCalm argon blowing: Gas Compressor

Implementation Method 7

continuous casting

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 8

continuous casting, heating and rolling

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 9

heating furnace heating

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 10

rolling processes is employed, utilizing specific chemical compositions and process parameters to produce steel bars with optimized mechanical properties

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS20260035775A1Method for producing and preparing steel bar for automotive bushings by means of ecological and economical arc furnace
Publication Date: 2026.02.05 BENGANG STEEL PLATES CO LTD

AI summary

A method for producing and preparing a steel bar for automotive bushings by means of an ecological and economical arc furnace is provided. The steer bar contains, in percentage by mass: 0.18-0.23% of C, 0.20-0.35% of Si, 0.42-0.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 0.82-1.00% of Cr, less than or equal to 0.25% of Ni, 0.41-0.53% of Mo, less than or equal to 0.15% of Cu, and the balance of Fe and inevitable impurities. By means of smelting in an ecological and economical arc furnace, LF refining, RH refining, continuous casting, a heating process and a rolling process, the method enables batch production of the steel bar for an automobile shaft sleeve by means of a continuous casting procedure using the ecological and economical arc furnace.