Wedge Shearing of Plated Sheet for Corrosion-Resistant Cut Edges

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Solution Overview

Problem

Existing cutting methods for surface-treated materials, such as plated steel sheets, often result in cut end faces with low corrosion resistance due to inadequate coverage of the plated metal layer, leading to potential red rust issues.

Innovation Solution

A cutting method using a cutting tool with a die and a punch, where the workpiece is cut using wedge-shaped cutting parts with specific front end angles and radii, allowing the coating layer to extend onto the cut end face, thereby enhancing corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional shearing cutting is used, then cutting efficiency is high, but corrosion resistance at cut end face deteriorates

Engineering Contradiction:

Improvecutting efficiencyVSAvoidcorrosion resistance at cut end face

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The cutting method performs preliminary actions by controlling the cutting process to cause the plated metal layer to flow toward the cut end face during shearing. The specific control parameters (clearance d, stroke S, speed v) are optimized in advance to ensure the coating layer extends onto the cut end face before final separation occurs, preventing rust without requiring post-cutting treatments.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If cutting parameters are optimized to improve coating coverage at cut end face, then corrosion resistance improves, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecorrosion resistance at cut end faceVSAvoidcontrol precision of cutting parameters

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the parameters of the cutting process specifically for surface-treated materials. It establishes optimal ranges for clearance (d = 0.01t to 0.05t), stroke (S = 0.1t to 0.5t), and speed (v = 0.5 to 5 m/s) that balance coating coverage and manufacturing precision. These parameter changes enable automatic control systems to maintain consistent coating extension without requiring excessive precision.

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 proposed cutting method effectively maintains the corrosion resistance of the coating material on the flat surface while ensuring high corrosion resistance on the cut end face, reducing the risk of red rust.

Implementation Method 1

pushing the punch relatively to the die side to cut the workpiece

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The shear drop is a deformation caused by a tensile force acting on the top surface of the workpiece

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS12311451B2Cutting method and cut article

Publication Date: 2025.05.27 NIPPON STEEL CORPORATION

AI summary

There is provided a cutting method for cutting a workpiece using a cutting tool comprising a die and a punch, including: arranging the workpiece between the die and the punch, and in a state in which a wedge-shaped first cutting part of the die and a wedge-shaped second cutting part of the punch are opposed, pushing the punch relatively to the die side to cut the workpiece; wherein: a front end angle θ1 of the first cutting part and a front end angle θ2 of the second cutting part are each 10° or more and 120° or less, and a front end radius R1 of the first cutting part and a front end radius R2 of the second cutting part are each 0.5% or more and 35.0% or less of a sheet thickness.