Boron Steel Hot Forming with Selective Cooling for Ductility
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Solution Overview
Problem
Existing methods for producing molded components with varying ductility, such as those using continuous furnaces or Al/Si coatings, fail to prevent scaling during the heating and forming processes, which affects the quality and properties of the final product.
Innovation Solution
A method involving high-strength boron steel with an Al/Si coating, where the material is heated homogeneously to form a diffusion layer, then selectively cooled in a multi-zone furnace to create areas with different microstructures, ensuring one area has higher ductility and the other higher strength, while preventing scaling through controlled temperature zones and potentially accelerated cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the semi-finished product is heated in a furnace under nitrogen atmosphere, then the material reaches the required temperature for hot forming, but scaling occurs during transfer and forming processes
Solution Approach 1:
The patent applies preliminary action by forming a diffusion layer on the steel blank before the hot forming process. The blank is heated to 830-950°C and held for a specific time to allow aluminum from the coating to diffuse into the base material, creating a protective diffusion layer that prevents scaling during subsequent processing
Solution Approach 2:
The patent converts the potentially harmful oxidation that occurs during heating into a beneficial protective layer. By controlling the heating process and diffusion time, the oxidation forms a diffusion layer that actually protects the material against scaling during transfer and forming, turning a harmful effect into a protective mechanism
2Stability of the object's composition
If the blank is cooled in a second zone to convert austenite to ferrite and/or pearlite, then the first type area achieves high ductility, but the strength is reduced
Solution Approach 1:
The patent applies local quality by creating different microstructural areas within the same component. The blank is divided into zones with different thermal histories: one zone is cooled to produce ferrite/pearlite for high ductility, while another zone is kept at austenitizing temperature for high strength, allowing each area to have optimized properties for its specific function
Solution Approach 2:
The patent segments the blank into different thermal zones during heating and cooling. The continuous furnace has multiple zones with different temperature profiles, and the blank is selectively cooled in certain areas while maintaining temperature in others, creating spatially separated microstructural regions with different properties
3Strength
If the temperature is kept high in the second type area to produce sufficient martensite, then the strength is increased, but the ductility is reduced
Solution Approach 1:
The patent applies local quality by creating different microstructural areas within the same component. The blank is divided into zones with different thermal histories: one zone is cooled to produce ferrite/pearlite for high ductility, while another zone is kept at austenitizing temperature for high strength, allowing each area to have optimized properties for its specific function
Solution Approach 2:
The patent applies parameter changes by precisely controlling temperature and time parameters in different zones. By adjusting the holding temperature (830-950°C) and time in the third zone, the process optimizes martensite formation for maximum strength while accepting the trade-off of reduced ductility in that specific area
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
The method effectively produces molded components with tailored ductility and strength properties, avoiding scaling issues and enabling specific adaptation for structural components like vehicle parts by forming a diffusion layer as an anti-corrosion and anti-scale layer.
Implementation Method 1
heated completely homogeneously to such a temperature and kept at this temperature level for a certain time that a Diffusion layer forms as an anti-corrosion or anti-scale layer, with material from the coating diffusing into the base material
Implementation Method 2
an area of the first type of blank is cooled down in a second zone of the furnace to a temperature at which austenite breaks down
Implementation Method 3
subjected to a hot-forming process for the purpose of forming into the molded component
Data Source
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AI summary
According to the method, a printed circuit board (7) that is severed from the strip material (4) comprising coated, high-strength boron steel is homogeneously heated in a furnace (11) having a plurality of temperature zones (8, 9, 10) first in a first zone (8) to a temperature of approximately 830ºC to 950ºC and maintainedat said temperature level for a define time (t). Thereafter, a region (12) of a first type of the printed circuit board (7) is cooled in a second zone (9) of the furnace (11) to a temperature of approximately 550ºC to 700ºC and maintained at said lowered temperature level for a defined time (t1). At the same time, a region (13) of a second type of the printed circuit board (7) in a third zone (10) of the furnace (11) is maintained at a temperature level of approximately 830ºC to 950ºC during a time (t2). After said heat treatment, a printed circuit board (7) is formed into a formed component (1) in a thermoforming process. The strip material is pre-coated with an aluminum silicon diffusion alloy.