Annular Hot-Stamping Blank With High-Emissivity Overlap Heating
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Solution Overview
Problem
Existing hot stamping processes face challenges in ensuring a process window for structural members with overlap parts, leading to reduced productivity and potential corrosion resistance issues due to varying sheet thicknesses and heating rates.
Innovation Solution
A blank for hot stamping is designed with multiple steel sheets forming an annular shape, where the overlap part has higher emissivity surfaces to enhance heating rate and reduce heating time, ensuring strength and rust resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the overlap part is heated to ensure strength through hot stamping, then the strength of the overlap part is improved, but the heating time increases and productivity decreases
Solution Approach 1:
The patent applies different surface treatments to different regions of the steel sheets. Specifically, the outer surfaces of the overlap part are treated to have high emissivity (60% or more) to accelerate heating, while other surfaces maintain lower emissivity. This local differentiation allows the overlap part to be heated quickly without requiring extended heating time for the entire blank, thus resolving the contradiction between ensuring strength and maintaining productivity.
2Productivity
If the thinnest plated steel sheet is heated quickly, then heating efficiency is improved, but alloying of the plating layer excessively proceeds and corrosion resistance deteriorates
Solution Approach 1:
The patent selectively treats only the outer surfaces of the overlap part with high emissivity coating, while leaving other surfaces (including the plating layer surfaces that need corrosion protection) untreated or with lower emissivity. This allows rapid heating of the overlap part through radiation without causing excessive alloying of plating layers in other regions, thus resolving the contradiction between heating efficiency and corrosion resistance.
Solution Approach 2:
The patent converts the potential harmful effect of high emissivity (which could cause excessive heating and plating layer alloying) into a beneficial localized effect by applying the high emissivity treatment only to specific outer surfaces of the overlap part. This controlled application ensures that the rapid heating benefit is achieved where needed (in the overlap part) without the harmful side effects in other regions.
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 solution allows for improved productivity and reduced energy consumption by ensuring a process window for the overlap part, maintaining strength and corrosion resistance in the structural member.
Implementation Method 1
the surface of the steel sheet provided with the surface-treated film is increased in emissivity and has higher heat transfer effect through radiation
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A blank (20) includes multiple steel sheets. The multiple steel sheets are disposed to form an annular shape in plan view of the blank (20) and joined to each other. The multiple steel sheets include steel sheets (21, 22). An end part of a first steel sheet (21) and an end part of a second steel sheet (22) form an overlap part (241). Among the multiple steel sheets, a steel sheet that forms a part having a smallest sheet thickness (tmin) in the blank (20) is a plated steel sheet. The overlap part (241) has a largest sheet thickness (tmax) in the blank (20). An emissivity of a surface (216, 226) of each of the steel sheets (21, 22) that is located on an outer side of the overlap part (241) is higher than an emissivity of at least one of other surfaces of the multiple steel sheets.