Hot-Stamped Steel Blank Plating Layout for Faster Overlap Heating

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Solution Overview

Problem

Existing hot stamping processes face challenges in ensuring a process window for structural members with overlap parts, leading to slower heating rates and reduced productivity due to excessive alloying of plating layers and potential corrosion resistance issues.

Innovation Solution

A blank for hot stamping comprising multiple steel sheets with controlled aluminum-based plating layers, where the deposition amount on some sheets is limited to 60 g/m² or less, facilitating quicker heating and ensuring rust resistance, while maintaining strength through controlled emissivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the blank includes an overlap part formed by partial overlapping of steel sheets to ensure strength, then the strength of the structural member is improved, but the heating rate decreases and the process window becomes difficult to ensure

Engineering Contradiction:
Improvestrength of overlap partVSAvoidheating rate
Core Design Contradiction:
StrengthVSSpeed

Solution Approach 1:

The patent applies different deposition amounts of aluminum-based plating layers to different regions of the steel sheets. Specifically, the overlap part has a deposition amount of 60 g/m² or less, while non-overlap parts can have higher deposition amounts. This local differentiation allows the overlap part to heat quickly while maintaining strength, resolving the contradiction between strength and heating rate.

Inventive Principle:
Principle #3Local quality

2Reliability

If the deposition amount of the plating layer is increased to ensure rust resistance, then the corrosion resistance is improved, but the heating rate decreases and energy consumption increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidheating rate
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent implements spatially varying deposition amounts of aluminum-based plating layers across different regions of the steel sheets. The overlap part uses a deposition amount of 60 g/m² or less for rapid heating, while other regions can have higher deposition amounts to ensure rust resistance. This local quality differentiation resolves the contradiction between corrosion resistance and heating rate.

Inventive Principle:
Principle #3Local quality

3Reliability

If the deposition amount of the plating layer is increased to ensure rust resistance, then the corrosion resistance is improved, but the energy consumption increases

Engineering Contradiction:
Improverust resistanceVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies different deposition amounts of aluminum-based plating layers to different regions: the overlap part has a deposition amount of 60 g/m² or less requiring less energy for heating, while non-overlap parts can have higher deposition amounts for rust resistance. This localized approach reduces overall energy consumption while maintaining necessary corrosion protection.

Inventive Principle:
Principle #3Local quality

4Strength

If the blank includes an overlap part with larger sheet thickness to ensure strength, then the strength is improved, but the productivity decreases due to slower heating

Engineering Contradiction:
Improvestrength of overlap partVSAvoidproductivity of structural member
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent changes the deposition amount parameter of the aluminum-based plating layer in the overlap part to 60 g/m² or less. This parameter change reduces the thermal mass and improves the heating rate of the overlap part, thereby increasing productivity while maintaining the necessary strength through controlled alloying of the plating layer.

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 solution allows for faster heating of overlap parts, ensuring a process window and improved productivity with reduced energy consumption and enhanced corrosion resistance in the resulting structural members.

Implementation Method 1

alloying of the plating layer of a steel sheet (non-overlap part) already heated to an intended temperature excessively proceeds, the diffusion layer becomes thicker

Methodology Applied
Scientific EffectAlloying:

Implementation Method 2

the diffusion layer becomes thicker, and the corrosion resistance (rust resistance) owing to the plating layer may deteriorate or be lost

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

the blank is heated until the microstructure thereof is austenitized

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 4

heated until the microstructure thereof is austenitized

Methodology Applied
Scientific EffectAustenite transformation:

Implementation Method 5

quenching the blank by holding the blank in the press tooling for heat dissipation (rapid cooling)

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP4703061A1Blank, method for producing structural member, and structural member
Publication Date: 2026.03.04 NIPPON STEEL CORPORATION
  • EP4703061A1 patent drawingFigure 1
  • EP4703061A1 patent drawingFigure 2
  • EP4703061A1 patent drawingFigure 3A

AI summary

A blank (20, 20A) includes multiple steel sheets. The multiple steel sheets are disposed to form an annular shape in plan view of the blank (20, 20A) and joined to each other. At least one of a first and a second steel sheets (21, 22) and a third steel sheet (23) are each a plated steel sheet having a base steel sheet (21a, 22a, 23a) and an aluminum-based plating layer (21b, 22b, 23b). An end part of the first steel sheet (21) and an end part of the second steel sheet (22) form an overlap part (241) having a largest sheet thickness (tmax). A deposition amount (W1, W2) of the plating layer (21b, 22b) of at least one of the first and the second steel sheets (21, 22) is 60 g/m2 or less and is less than a deposition amount (W3) of the plating layer (23b) of the third steel sheet (23).