Conical Friction Welding Element With Discharge Grooves for Sheet Joining
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Solution Overview
Problem
The existing friction element welding techniques face challenges in concentrating frictional heat at a predetermined position, leading to difficulties in penetrating the top sheet, especially when both sheets are steel, resulting in dispersed heat and inadequate joining.
Innovation Solution
The development of a friction element welding element with a conical pin and fluidized-metal discharge grooves allows for concentrated heat generation and smooth discharge of chippings, enabling successful penetration and joining of metal sheets, including steel and light metal combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a pin with apex contact is used to generate frictional heat during press penetration, then frictional heat should be concentrated at a predetermined position, but the pin's central axis position fluctuates significantly causing heat dispersion
Solution Approach 1:
The pin is segmented into multiple sections along its length, with each section having a different diameter. This segmentation allows the pin to maintain stability during press penetration while the apex generates concentrated frictional heat, preventing both heat dispersion and position fluctuation simultaneously.
Solution Approach 2:
Different sections of the pin have different local properties (diameters) optimized for different functions: the apex section generates concentrated heat, while other sections provide structural stability and maintain central axis position during penetration, resolving the contradiction between heat concentration and position stability.
2Strength
If general-purpose melt welding methods are used to join steel sheets, then strong joining can be achieved, but intermetallic compounds form causing extreme brittleness when joining steel and light metal
Solution Approach 1:
The invention replaces thermal-melt welding processes with a mechanical friction-based press penetration process. The element is pressed into the stacked sheets and rotated, generating frictional heat that softens the material locally without melting it, avoiding intermetallic compound formation while achieving strong joints between dissimilar metals.
Solution Approach 2:
The process changes the fundamental parameters of the joining method from high-temperature melting to controlled frictional heating with plastic deformation. This parameter change allows joining of steel and light metal sheets without forming brittle intermetallic compounds, while maintaining joint strength through mechanical interlocking and localized bonding.
3Power
If the pin rotates at high speed during press penetration, then frictional heat is generated, but the heat is dispersed and the top sheet is not softened easily
Solution Approach 1:
The segmented pin design concentrates the frictional heat generation at the apex section while the other sections provide structural support. This segmentation ensures that the power input is localized to the apex, creating high temperature concentration at the intended position rather than dispersing heat throughout the entire pin-sHEET interface.
Solution Approach 2:
The pin apex is designed with a specific curved geometry that concentrates the contact area, ensuring that frictional heat is generated at a focused point rather than being dispersed over a large area. This curvature optimization enhances localized heating while maintaining rotational stability.
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 solution ensures effective friction element welding of sheet sets with both steel and light metal sheets, achieving strong and reliable joints by maintaining the pin's position and concentrating frictional heat, thereby enhancing industrial efficiency.
Implementation Method 1
friction element welding being performed by press penetrating an element into a sheet set while rotating the element... frictional heat is generated concentratedly at a predetermined position
Data Source
AI summary
In performing friction element welding of a sheet set constituted by two or more metal sheets, an element is press penetrated into the sheet set. The element may include a round columnar mandrel; a disc-shaped collar provided at an upper end face of the mandrel; and a conical pin extending from a lower end face of the mandrel. The element has a plurality of fluidized-metal discharge grooves arranged spirally in a flat area of the lower end face of the mandrel, the flat area excluding the pin. Alternatively, the element may include a round columnar mandrel having a lower end face that forms a conical face with an apical angle αm, the conical face having one or more pairs of chippings discharge grooves or having a plurality of cutting edges, the chippings discharge grooves each extending in a curved manner from an apex of the conical face.