Sheet Metal Patch Assembly Coating for Hot-Formed Corrosion Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing sheet metal components, particularly in motor vehicle bodywork, fail to provide effective corrosion protection in the gaps between overlapping sheets during hot forming and subsequent joining processes, leading to accelerated corrosion due to incomplete coating penetration and capillary action.
Innovation Solution
Applying a high-temperature-resistant corrosion protection coating between the base and patch sheets before hot forming, which is then 'burned in' during the process, ensuring permanent protection without requiring additional energy or post-coating steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard KTL coating process is applied to the entire component after hot forming, then the outer surfaces receive adequate corrosion protection, but the gaps between overlapping sheets remain unprotected due to incomplete coating penetration
Solution Approach 1:
A corrosion protection coating is applied to the gap areas between overlapping sheets before the hot forming process. This preliminary coating application ensures that the gaps are protected before assembly, eliminating the problem of incomplete coating penetration that occurs with post-assembly KTL coating.
Solution Approach 2:
The corrosion protection approach is differentiated by location: the gap areas between overlapping sheets receive a specialized high-temperature-resistant coating applied before assembly, while the outer surfaces receive the standard KTL coating after assembly. This local quality differentiation ensures optimal protection for each specific area's corrosion risks.
2Strength
If the component is heated to high temperature for hot forming, then the desired microstructural transformation and strength are achieved, but any organic coating present would be destroyed or degraded
Solution Approach 1:
The coating material parameters are specifically selected to withstand the high temperatures of hot forming. A high-temperature-resistant organic coating is applied before assembly, and the hot forming temperature and duration are controlled to achieve the necessary microstructural transformation while maintaining the coating's integrity.
Solution Approach 2:
The solution uses a composite approach by combining the high-temperature-resistant organic coating with the metal substrate, creating a protected component unit that can withstand the thermal conditions of hot forming while maintaining both the metal's microstructural transformation capability and the coating's protective function.
3Ease of manufacture
If gap areas between sheets are left open for assembly, then the component unit can be formed and joined, but corrosion-promoting substances can penetrate through capillary action and accelerate corrosion
Solution Approach 1:
The gap areas are coated with corrosion protection material before the assembly process. This preliminary protective action ensures that when the sheets are joined and gaps remain, the corrosion protection is already in place, preventing capillary penetration of corrosion-promoting substances while maintaining assembly capability.
4Ease of manufacture
If an aluminum/silicon compound coating is applied to the metal substrate, then corrosion protection is provided, but the coating provides significantly poorer corrosion protection compared to zinc coating
Solution Approach 1:
The solution uses a composite coating system: the base metal substrate retains its aluminum/silicon compound coating for manufacturing ease and basic protection, while an additional high-temperature-resistant organic corrosion protection coating is applied to critical gap areas. This composite approach combines the advantages of both coating types, achieving superior corrosion protection where it is most needed.
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 method provides comprehensive corrosion protection in the gaps between sheet metal components, preventing liquid ingress and significantly reducing corrosion rates, while allowing for a standard KTL coating on the entire component post-forming.
Implementation Method 1
the component unit thus formed from base sheet and patch sheet is heated to a temperature suitable for hot forming and is then hot formed
Implementation Method 2
which can also serve to seal this gap and thus prevent the penetration of corrosion-promoting substances
Implementation Method 3
is preferably subsequently or simultaneously subjected to partial or total cooling or quenching for the purpose of a targeted microstructural transformation
Data Source
Figure 1~2
AI summary
The invention relates to a method for producing components from sheet metal, wherein at least one patch sheet (2) is placed on a base sheet (1) to form a material doubling and is positionally securely fixed, the component unit thus formed, comprising base sheet (1) and patch sheet (2), is heated to a temperature suitable for hot forming and is then hot-formed to form the component and, preferably subsequently or simultaneously, is subjected to partial or total cooling or quenching for the purpose of a specific structure conversion, wherein, for the purpose of improved corrosion protection, the base of sheet (1) in the contact region of the patch sheet (2), or the patch sheet (2) on the side thereof facing the base sheet (1), or both base sheet (1) and patch sheet (2) in the corresponding area are coated with an anti-corrosion coating (6) that is resistant to the temperatures occurring during the hot forming, before the patch sheet (2) is placed on the base sheet (1).