Cold-Bent Reinforcement Tab for Coated Press-Hardened Steel

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Solution Overview

Problem

Reinforcement members made of high-strength press hardened steel coated with zinc or aluminum, used to prevent deformation in vehicle parts, face issues with attachment to surrounding parts due to potential fracture and coating damage during bending, leading to reduced mechanical properties and corrosion resistance.

Innovation Solution

The reinforcement member features a tab made from a cold-bent part with an elongation of the extrados between 10% and 25%, allowing for significant angle bending without fracturing the reinforcement member or damaging the coating, even with thick reinforcement members, thus ensuring reliable attachment to surrounding parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tab is bent at a high angle to attach the reinforcement member to surrounding parts, then the attachment reliability is improved, but the reinforcement member may fracture or the coating may crack

Engineering Contradiction:
Improveattachment reliabilityVSAvoidmechanical properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent controls the elongation parameter of the extrados during bending to be between 10% and 25%, which is a specific parameter change that prevents coating crack initiation while enabling high-angle bending for reliable attachment

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the tab is bent at a high angle to attach the reinforcement member to surrounding parts, then the attachment reliability is improved, but the coating may crack reducing corrosion resistance

Engineering Contradiction:
Improveattachment reliabilityVSAvoidcorrosion resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent controls the elongation parameter of the extrados during bending to be between 10% and 25%, which is a specific parameter change that prevents coating crack initiation while enabling high-angle bending for reliable attachment

Inventive Principle:
Principle #35Parameter changes

3Strength

If the reinforcement member has increased thickness to improve impact resistance, then the protective function is improved, but the bending operation becomes more prone to cause fracture

Engineering Contradiction:
Improveimpact resistanceVSAvoidfracture risk
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent controls the elongation parameter of the extrados during bending to be between 10% and 25%, which is a specific parameter change that prevents coating crack initiation while enabling high-angle bending for reliable attachment

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

This solution enables reliable attachment of the reinforcement member to surrounding parts without fracturing or damaging the coating, maintaining mechanical properties and corrosion resistance, effectively preventing deformation in vehicle parts during impacts.

Implementation Method 1

said tab being made of a cold bent part of the body, the elongation of the extrados being comprised between 10% and 25%

Methodology Applied
Scientific EffectCold bending: Cold-forming

Data Source

PatentEP3541687B1Reinforcement member comprising a cold bent tab
Publication Date: 2021.04.28 ARCELORMITTAL SA
  • EP3541687B1 patent drawingFigure 1~2
  • EP3541687B1 patent drawingFigure 3
  • EP3541687B1 patent drawingFigure 4

AI summary

The reinforcement member (1) comprises a body (2) made of a press hardened steel having a tensile strength greater or equal to 1200 MPa coated with a zinc- based coating or with an aluminum-based coating, said body (2) extending along a main direction (A), the reinforcement member further comprising at least one tab (16) extending from the body (2) along a transversal direction (B) forming a non-zero angle (a) with the main direction (A), the bend (18) between the body (2) and the tab (16) defining an intrados (20) and an extrados (22). Said tab (16) is made of a cold bent part of the body (2), the elongation of the extrados (22) being comprised between 10% and 25%.