AlMg5 Blind Rivet Nut Forming for Strength and Simpler Manufacturing
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Solution Overview
Problem
Existing manufacturing methods for blind rivet nuts are complex, expensive, and do not effectively utilize aluminum alloys for improved mechanical strength, particularly due to the need for multiple cold forging stages and intermediate heat treatments.
Innovation Solution
A blind rivet nut made from an aluminum alloy with a Magnesium mass percentage range of 4.5% to 5.6%, combined with cold forging, annealing, and thread forming, where cold forging is completed before thermal treatment to simplify the process and enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double-cold manufacturing process with intermediate heat treatment is used, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the cold striking and cold coining operations into a single integrated die set, eliminating the need for separate manufacturing steps and intermediate heat treatment. The first and second cold coining operations are performed sequentially in one setup, simplifying the overall manufacturing process while maintaining dimensional accuracy.
Solution Approach 2:
The manufacturing process is segmented into distinct operational phases within a single die: initial cold striking to form the basic shape, followed by first cold coining for dimensional refinement, and second cold coining for final precision. This segmentation allows each operation to be optimized independently while avoiding the complexity of multiple separate process steps.
2Object-affected harmful factors
If aluminum alloy is used instead of steel, then resistance to galvanic corrosion is improved, but mechanical strength decreases
Solution Approach 1:
The patent applies specific parameter changes to the aluminum alloy, including precise control of magnesium content (4.5-5.6% by weight) and the application of controlled plastic deformation through cold coining. These parameter changes transform the aluminum alloy's mechanical properties, achieving tensile strength ≥300 MPa and elongation ≥10%, thereby eliminating the strength deficiency while maintaining corrosion resistance.
Solution Approach 2:
The patent creates a composite microstructure within the aluminum alloy through controlled cold working and heat treatment, resulting in a refined grain structure that combines the corrosion resistance of aluminum with enhanced mechanical strength. The specific alloy composition and processing create a material that exhibits properties superior to conventional aluminum alloys.
3Ease of manufacture
If cold forging is performed before heat treatment, then manufacturing process is simplified, but material ductility may be reduced
Solution Approach 1:
The patent performs preliminary cold forging operations to establish the basic geometry and initiate plastic deformation before heat treatment. This preliminary action creates a favorable stress distribution and grain structure that prepares the material for subsequent forming operations while maintaining adequate ductility through the controlled sequence of operations.
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 provides a cost-effective and efficient method for producing blind rivet nuts with improved mechanical strength and resistance to inter-granular corrosion, achieving superior hardness and stability without excessive material defects.
Implementation Method 1
cold forging of a blank made of steel or an aluminum alloy
Implementation Method 2
annealing heat treatment of the blank
Data Source
Figure 1~6
Figure 3~5
AI summary
The present invention provides a blind rivet nut, a manufacturing method making the same as well as a combination of at least one component having an opening and a blind rivet nut fastened in said opening, wherein the blind rivet nut is made of an aluminum alloy of AlMg5 which comprises a Magnesium mass percentage wMg in the range of 4.5 %m/m≤wMg≤5.6 %m/m, and it further comprises at least one component selected from the following group of manganese (MN), chromium (Cr), zinc (Zn), copper (Cu), iron (Fe), titanium (Ti), silicon (Si) wherein the blind rivet nut has a head forming a first axial end, a subsequent crimp section of a shaft deformable into a crimping bead (8) and a thread section of the shaft providing a radial inner thread.