Aluminum-Coated Blank Joining to Prevent Weld Segregation
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Solution Overview
Problem
Existing methods for manufacturing aluminum-coated blanks face challenges in maintaining the hardness and physical properties of joints, particularly during hot-stamping, as the aluminum-silicon coating layer can lead to segregation and deterioration of mechanical properties when laser-welded, resulting in inadequate energy absorption in vehicle crash scenarios.
Innovation Solution
A method involving the alignment and laser-beam irradiation of aluminum-coated steel sheets with a filler wire to form a joint at a predetermined angle, ensuring sufficient dilution of the coating layer components and maintaining a martensite structure, thereby preventing segregation and enhancing the joint's hardness and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum-coated steel sheets are laser-welded together, then the manufacturing efficiency and joint strength are improved, but the aluminum coating layer causes segregation and deterioration of mechanical properties in the joint
Solution Approach 1:
The patent removes the aluminum coating layer from the steel sheets before laser welding. This extraction of the harmful coating layer prevents aluminum segregation and intermetallic compound formation in the weld joint, thereby eliminating the deterioration of mechanical properties while maintaining the benefits of laser welding
Solution Approach 2:
The patent performs coating layer removal as a preliminary action before the laser welding process. By removing the aluminum coating in advance, the subsequent welding process operates on clean steel surfaces, preventing coating-related defects from forming in the first place
2Stability of the object's composition
If the aluminum coating layer is removed before welding, then the joint composition stability is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent replaces complex mechanical coating removal methods with a simpler process that utilizes the laser welding heat itself or a straightforward preprocessing step, reducing overall process complexity while achieving the desired coating removal
Solution Approach 2:
The patent modifies the surface condition parameter of the steel sheets by removing the coating layer, transforming the problem from a compositional issue to a surface preparation issue that can be addressed with established industrial processes
3Productivity
If the joint formation speed is increased, then the productivity is improved, but the aluminum coating layer components are not sufficiently diluted, causing segregation
Solution Approach 1:
By removing the aluminum coating layer before welding, the patent eliminates the source of segregation entirely. This allows the welding process to proceed at high speeds without the risk of aluminum component segregation, as the coating layer that would cause the problem is no longer present
Solution Approach 2:
The preliminary removal of the coating layer enables subsequent high-speed welding operations to proceed without composition stability issues, as the harmful aluminum coating is already gone before the rapid welding process begins
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 minimizes joint breakage and maintains the hardness of the aluminum-coated blank to be equal to or greater than the base steel sheets, ensuring improved mechanical properties and energy absorption capabilities.
Implementation Method 1
melting the facing portions of the aluminum-coated steel sheets and the filler wire by laser beam irradiation from a laser head
Implementation Method 2
melting the facing portions of the aluminum-coated steel sheets and the filler wire
Implementation Method 3
ensuring sufficient dilution of the coating layer components
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Disclosed are an aluminum-coated blank, a manufacturing method thereof, and an apparatus for manufacturing the same. The blank includes two or more aluminum-coated steel sheets connected together by a joint, each of the steel sheets including: a base steel sheet including 0.01-0.5 wt% of carbon, 0.01-1.0 wt% of silicon, 0.5-3.0 wt% of manganese, greater than 0 but not greater than 0.05 wt% of phosphorus, greater than 0 but not greater than 0.01 wt% of sulfur, greater than 0 but not greater than 0.1 wt% of aluminum, greater than 0 but not greater than 0.001 wt% of nitrogen, and the balance of iron and other inevitable impurities; and a coating layer including aluminum and formed on at least one surface of the base steel sheet.