Preformed Sheet Metal Edge Heating for Crack-Resistant Forming
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Solution Overview
Problem
Existing methods for producing components from high-strength steels face challenges in reducing work hardening and notch effects at cut edges, leading to increased sensitivity to cracks during forming, which limits formability and reliability.
Innovation Solution
A method involving a pre-formed contour of a circuit board, where edge areas are heated to at least 600 °C for a maximum of 10 seconds to eliminate work hardening and structural damage, followed by further forming at ambient temperature, allowing for increased formability and reduced crack sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical cutting methods (shearing or punching) are used to cut sheet metal blanks, then cutting cost is reduced and productivity is improved, but work hardening and notch effects occur at cut edges leading to increased crack sensitivity during forming
Solution Approach 1:
The patent applies preliminary action by performing heat treatment on the cut edges before the forming process. The method heats the cut edges to 600-950°C for a short duration (0.02-10 seconds) to eliminate work hardening and notch effects created by mechanical cutting, thereby preventing crack sensitivity during subsequent forming operations while maintaining high productivity from mechanical cutting methods
Solution Approach 2:
The patent applies parameter changes by temporarily changing the temperature parameter of the cut edges. The edges are heated to 600-950°C (above the Ac1 transformation point) for a brief period to alter the material properties, reducing hardness and eliminating residual stresses, then rapidly cooled to restore strength while maintaining improved formability
2Weight of moving object
If high-strength steels with yield strengths above 600 MPa are used to reduce wall thickness, then weight reduction is achieved, but formability decreases and crack sensitivity increases during cold forming
Solution Approach 1:
The patent applies parameter changes by temporarily heating the cut edges to 600-950°C to alter the material properties of high-strength steels. This thermal parameter change reduces the yield strength temporarily, enabling cold forming operations on edges that would otherwise be too brittle, then rapid cooling restores the high strength while maintaining improved formability
Solution Approach 2:
The patent applies preliminary action by performing heat treatment on the cut edges before cold forming operations. This preliminary heating eliminates work hardening and reduces notch effects, preparing the high-strength steel edges for successful forming without cracking, thereby enabling weight reduction through thinner walls
3Shape
If cut edges are raised or folded upwards during forming operations, then component geometry is improved, but edge areas are subjected to particular stress leading to premature failure
Solution Approach 1:
The patent applies preliminary action by heating the cut edges to 600-950°C before performing forming operations that raise or fold edges. This preliminary heat treatment eliminates work hardening and reduces residual stresses, allowing the edges to be formed into complex geometries without premature failure during or after the forming process
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
Significantly enhances the formability of materials, reduces crack sensitivity, and enables the production of complex geometries without additional joining operations, improving the hole expansion capacity and fatigue strength of components.
Implementation Method 1
the edge areas intended for forming, but at least the edge areas already subjected to the first forming process, are heated to a temperature of at least 600 °C for a maximum duration of 10 seconds
Implementation Method 2
undergoes a short heat treatment (max. 10 seconds) at at least 600 °C in the areas of the sheared edges after optional punching and/or cutting operations
Data Source
AI summary
The invention relates to a method for producing a component by further forming of a preformed contour of a blank, wherein the blank which has previously been cut to size at room temperature from a strip or a sheet is subjected to a first shaping operation at ambient temperature after optional further production steps carried out at ambient temperature, such as for example stamping or cutting operations to achieve clearances or apertures, in selected edge regions that have been cold-hardened by the stamping or cutting operations to obtain a preformed contour. Optionally the edge regions that are already intended for shaping, but at least the edge regions that have already undergone the first shaping are thereby heated to a temperature of at least 600°C for a maximum time of 10 seconds and, at any desired time after this thermal treatment, the edge regions are subjected to a second shaping or to further shaping operations at ambient temperature with prior thermal treatments in each case.