Cold-Rolled Silicon Steel Strip Joints Heated to Prevent Fracture

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Solution Overview

Problem

The existing methods for cold-rolling silicon steel sheets with high Si content are unable to prevent fractures at the joint portion during the cold rolling process to an operationally acceptable level, leading to productivity losses and increased production costs.

Innovation Solution

The solution involves controlling the rolling temperature of the joint portion by heating it to 50°C or higher before cold rolling, which effectively suppresses the occurrence of fractures in the joint portion during the cold rolling process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If laser welding is used to join leading and trailing materials, then joint strength and workability are improved, but the probability of fracture at the joint portion during cold rolling increases

Engineering Contradiction:
Improvejoint strengthVSAvoidfracture resistance during cold rolling
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the temperature parameter of the joint portion by heating it to 50°C or higher before cold rolling. This parameter change makes the joint portion more ductile and less prone to fracture during the cold rolling process, while maintaining the strength benefits of laser welding.

Inventive Principle:
Principle #35Parameter changes

2Strength

If conventional welding optimization is performed, then joint strength is improved, but fracture prevention during cold rolling remains insufficient

Engineering Contradiction:
Improvejoint strengthVSAvoidfracture occurrence
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention applies preliminary heating action to the joint portion before the cold rolling process. By heating the joint portion to 50°C or higher in advance, the material becomes more ductile and can withstand the deformation stresses of cold rolling without fracturing, thereby preventing the harmful effect of fractures.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If cold rolling is performed without interruption, then productivity is improved, but joint portion fractures cause line stopping and productivity decrease

Engineering Contradiction:
Improvecontinuous rolling efficiencyVSAvoidjoint stability during rolling
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By changing the temperature parameter of the joint portion through heating, the invention ensures joint stability during continuous cold rolling. This prevents fractures that would otherwise cause line stopping, thereby maintaining high productivity and continuous operation.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If joint portion heating is applied, then fracture rate is reduced, but additional heating equipment and process complexity are required

Engineering Contradiction:
Improvejoint fracture resistanceVSAvoidheating system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention introduces a heating device as an intermediary component between the joining device and the cold rolling mill. This intermediary heating system prepares the joint portion by raising its temperature to 50°C or higher, making it more ductile and resistant to fracture during subsequent cold rolling, while adding manageable complexity to the overall system.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This approach significantly reduces the fracture rate of the joint portion, allowing for stable cold-rolling of silicon steel sheets, thereby improving productivity and reducing production costs.

Implementation Method 1

a heating device (14) which heats the joint portion (Sj) of the joined steel strip (S)

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4098378B1Cold-rolled steel strip manufacturing facility and method for manufacturing cold-rolled steel strip
Publication Date: 2025.06.18 JFE STEEL CORP
  • EP4098378B1 patent drawingFigure 1~2

AI summary

A cold-rolled steel strip manufacturing facility 1 includes a joining device 12 that joins the trailing end of a preceding steel strip and the leading end of the following steel strip to form a joined steel strip S, a looper 13 that stores the joined steel strip S, a heating device 14 that heats the joint portion between the preceding steel strip and the following steel strip over the entire width direction, and a cold rolling mill 16 that cold rolls the joined steel strip S for which the joint portion was heated by the heating device 14. The heating device 14 is switchable between an output state and a non-output state, and during the period in which the joint portion passes through the heating device 14, is switched to the output state.