Ridge Preforming of High-Strength Steel for Accurate Press Forming
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Solution Overview
Problem
High-strength steel sheets used in vehicle components face challenges such as shape fixation failure and increased risk of breakage during press forming due to high elastic strain recovery, making it difficult to achieve both lightweight and safe vehicle bodies while maintaining dimensional accuracy and productivity.
Innovation Solution
A press forming method that involves producing an intermediate molding with a ridge and then press forming it into a final shape, enhancing deformation strength without annealing, thereby improving the vehicle component's ability to absorb impact energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-strength steel sheet is used to improve vehicle safety performance, then strength and energy absorption capacity are improved, but shape fixation failure and wrinkle occur more frequently during press forming
Solution Approach 1:
The patent applies preliminary action by performing intermediate press forming to create a ridge structure before final press forming. This intermediate step pre-deforms the material in a controlled manner, creating a ridge that serves as a stress distribution feature during subsequent forming operations, thereby preventing shape fixation failure and wrinkle while maintaining the high strength characteristics of the steel sheet
Solution Approach 2:
The patent utilizes parameter changes by controlling the forming conditions during intermediate press forming to create a specific ridge structure. By adjusting forming parameters such as load, speed, and tooling geometry, the material undergoes controlled plastic deformation that creates a ridge with optimized stress distribution characteristics, resolving the contradiction between maintaining strength and preventing forming defects
2Strength
If high-strength steel sheet is used, then vehicle safety performance is improved, but elastic strain recovery increases causing dimensional accuracy to deteriorate
Solution Approach 1:
The intermediate press forming creates a ridge structure that acts as a preliminary deformation feature. This ridge structure modifies the stress distribution and strain hardening characteristics of the high-strength steel, reducing elastic strain recovery during final forming and improving dimensional accuracy while preserving the strength benefits
Solution Approach 2:
The patent applies local quality by creating a ridge structure at specific locations through intermediate press forming. This localized deformation feature concentrates strain hardening and modifies material properties in specific regions, thereby controlling elastic strain recovery locally while maintaining overall part strength and dimensional accuracy
3Strength
If high-strength steel sheet is used, then vehicle safety performance is improved, but ductility decreases increasing breakage risk during press forming
Solution Approach 1:
The intermediate press forming performs preliminary plastic deformation to create the ridge structure before final forming. This pre-deformation process distributes strain more evenly and creates a favorable stress state that reduces the risk of sudden breakage during subsequent forming operations, thereby improving reliability while maintaining strength
Solution Approach 2:
The patent utilizes parameter changes by controlling the intermediate press forming conditions to create a ridge with optimized geometry. This controlled deformation modifies the material's strain distribution and work hardening characteristics, reducing stress concentrations that could lead to breakage while preserving the high strength properties
4Strength
If hot press forming or induction hardening is used to enhance crash safety performance, then deformation strength is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent applies self-service by using the press forming process itself to create the ridge structure and achieve the desired strength characteristics through controlled plastic deformation and strain hardening. This eliminates the need for separate hot press forming or induction hardening equipment and processes, reducing device complexity and manufacturing cost while maintaining deformation strength
Solution Approach 2:
The patent extracts the strengthening function from separate thermal processing steps (hot press forming, induction hardening) and integrates it into the mechanical press forming process. By creating a ridge structure through controlled plastic deformation, the patent achieves the desired deformation strength without requiring additional heating or thermal treatment equipment
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 effectively work-hardens the vehicle component, increasing its deformation strength and energy absorption capacity, allowing for improved crash safety performance without the need for hot press forming or induction hardening, while maintaining a reduced manufacturing cost and vehicle weight.
Implementation Method 1
This method effectively work-hardens the vehicle component, increasing its deformation strength and energy absorption capacity
Implementation Method 2
the high-strength steel sheet shows large elastic strain recovery, and this makes it difficult to ensure dimensional accuracy required for the final product
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Disclosed is a press forming method press forming a workpiece between a die and a punch, while pushing the punch into the die by means of a relative motion of the die and the punch, the method includes: producing an intermediate molding (100B) having ridges (100d) formed in predetermined parts of the workpiece, and then press forming the intermediate molding (100B) into a final shape, to thereby substantially thicken and work-harden the predetermined parts of the workpiece.