Phosphating Steel with Pre-Deposited Activation Particles

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Solution Overview

Problem

Existing methods for producing anti-corrosive coated steel products often result in incomplete removal of functional coatings, leading to uneven phosphating surfaces with poor adhesive adhesion due to residual coating layers obstructing activation particles from reaching the steel surface.

Innovation Solution

Applying additional activation particles to the steel product before or during tempering and coating steps, allowing for improved phosphating even if the functional coating is not completely removed, enhancing the uniformity and adhesion of the phosphate layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a functional coating is applied to the steel flat product before forming, then the formability and adhesion during forming are improved, but residues of the functional coating remain on the surface after cleaning, preventing uniform phosphating

Engineering Contradiction:
ImproveformabilityVSAvoiduniformity of phosphate layer
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Activation particles are applied to the steel flat product before the functional coating is applied, so that when phosphating occurs later, the activation particles are already in position to promote uniform phosphate crystal formation. This preliminary placement of activation particles ensures that even with functional coating residues present, the phosphating process can proceed uniformly across the surface.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If a cleaning step is performed to remove the functional coating, then the surface should be clean for phosphating, but the cleaning step is incomplete and residues remain, leading to uneven phosphate crystal formation

Engineering Contradiction:
Improvecleanliness of surfaceVSAvoidconsistency of phosphate layer
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The phosphating process itself serves to address the presence of functional coating residues. By applying activation particles beforehand, the phosphating process can proceed effectively even without complete removal of functional coating residues, as the activation particles compensate for the imperfect surface cleanliness and promote uniform phosphate crystal formation regardless of residual contamination.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If activation particles are applied only after cleaning, then the phosphating should be uniform, but the functional coating residues block the activation particles from reaching the steel surface, resulting in poor adhesion

Engineering Contradiction:
Improveuniformity of activationVSAvoidadhesive adhesion
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

Activation particles are applied to the steel flat product before the functional coating is applied, ensuring that the activation particles are already embedded or adhered to the surface. This preliminary application allows the activation particles to overcome the blocking effect of functional coating residues, as they are already in contact with the steel surface and can effectively promote uniform phosphate crystal formation with improved adhesive adhesion.

Inventive Principle:
Principle #10Preliminary action

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 results in a more uniform, finely crystalline phosphate layer with improved mechanical stability and adhesive properties, reducing porosity and enhancing corrosion resistance.

Implementation Method 1

Applying activation particles to the formed component from step (E)... Applying a phosphate coating to the formed component from step (F)... yields improved phosphated surfaces... exhibiting in particular better adhesive adhesion... a more uniform, finely crystalline phosphate layer

Methodology Applied
Scientific EffectNucleation: Nucleation

Implementation Method 2

a more uniform, finely crystalline phosphate layer with improved mechanical stability and adhesive properties

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

Applying a phosphate coating to the formed component from step (F)... a phosphate layer is formed that consists in areas of differently sized zinc phosphate crystals

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP3856947B1Method for improving the phosphatability of metal surfaces which are provided with a temporary pre- or post-treatment
Publication Date: 2024.09.04 THYSSENKRUPP AG
  • EP3856947B1 patent drawingFigure 1
  • EP3856947B1 patent drawingFigure 2

AI summary

The present invention relates to a method for producing a formed component, comprising at least the following steps: (A) providing a steel strip product; (B) skin-passing the steel strip product from step (A); (C) applying a functional coating to the steel strip product from step (B); (D) forming the steel strip product from step (C) in order to obtain a formed component; (E) removing the functional coating from the formed component from step (D); (F) applying activation particles to the formed component from step (E); and (G) applying a phosphate coating to the formed component from step (F), wherein additional activation particles are applied to the steel strip product before and/or during step (B) and/or before and/or during step (C).