Ultra-High Strength Steel Hot Forming for Powertrain Components
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Solution Overview
Problem
Ultra-high strength steel, such as boron steel, is difficult to form into complex shapes and geometric dimensions required for automotive powertrain components due to its limited formability with conventional cold-forming technologies, leading to components that are prone to cracking and fracture.
Innovation Solution
A method involving pre-forming ultra-high strength steel blanks into predetermined shapes through cold-forming, followed by heat treatment in an inert atmosphere, and quenching using a water-cooled die to achieve the desired geometric dimensions and tolerance, allowing for the formation of features like spline teeth and other complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cold-forming technologies are used on ultra-high strength steel, then the steel can be formed into basic shapes, but the formability is limited and the component is prone to cracking and fracture
Solution Approach 1:
The patent applies hot forming technology which changes the temperature parameter of the ultra-high strength steel from ambient to austenite transformation temperature range, fundamentally altering the material's formability characteristics and enabling complex geometric shapes without cracking
Solution Approach 2:
The patent utilizes the phase transition of ultra-high strength steel from martensite (cold-formed state) to austenite (heated state) and back to martensite (quenched state), leveraging the austenite phase's superior ductility for forming complex geometries while maintaining final strength
2Weight of moving object
If ultra-high strength steel is used to reduce component weight, then weight reduction is achieved, but formability and weldability are negatively affected
Solution Approach 1:
By changing the temperature parameter during manufacturing (hot forming), the patent temporarily improves formability of ultra-high strength steel, allowing weight reduction benefits to be realized without sacrificing manufacturability
Solution Approach 2:
The patent applies preliminary heating to transform the steel into austenite phase before forming, which preliminary prepares the material with enhanced formability characteristics needed for complex powertrain component geometries
3Device complexity
If conventional cold-forming is used, then manufacturing process is simple, but required geometric dimensions and tolerances cannot be achieved
Solution Approach 1:
The patent changes the temperature parameter during forming to enable achievement of tight geometric tolerances (e.g., ±0.05mm) that are impossible with cold-forming, while the overall process remains integrated and efficient
4Ease of manufacture
If aluminum or HSLA steel is used for powertrain components, then formability is good and manufacturing is easy, but weight reduction and impact energy absorption are limited
Solution Approach 1:
The patent applies hot forming parameter changes to ultra-high strength steel, achieving formability comparable to aluminum and HSLA while simultaneously realizing weight reduction and enhanced impact energy absorption properties
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 enables the production of lightweight, high-strength components with improved tolerance and reduced material usage, enhancing manufacturing flexibility and reliability while reducing costs by minimizing unnecessary trimming and die wear.
Implementation Method 1
quenching the heat treated blank of steel. Quenching may include forming a plurality of spline teeth along the blank of steel or finalizing the predetermined form using a water cooled quenching die
Implementation Method 2
The inert atmosphere may be an induction oven or an induction chamber. Additionally, the heat treating may be partially or completely localized
Data Source
AI summary
A component and method for forming the component utilizing ultra-high strength steel is provided. The method includes the steps of providing a blank of ultra-high strength steel and forming the blank into an unfinished component. Next, heating the unfinished component and moving an inner tooling member and an outer tooling member relative to one another to sandwich the heated component therebetween. Further, moving a punch member from a withdrawn, unactuated position to an extended, actuated position to contact the component while sandwiched between the inner and outer tooling members to form a feature including at least one of a thickened region having an increased thickness relative to an adjacent region, a recessed annular groove, a recessed pocket, a through hole, a flange, a through hole having a tab extending outwardly therefrom, or spline teeth. Then, quenching the feature.