Composite Friction Stir Welding Probe for Narrow Seam Rigidity
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Solution Overview
Problem
Friction stir welding probes made of heat-resistant metallic materials are prone to bending under external forces or moments, leading to reduced durability and unsuitability for narrow welds.
Innovation Solution
A welding tool with a probe composed of two different materials, where a ceramic material with high modulus of elasticity and thermal stability forms a support area and a metallic material with high thermal conductivity and friction properties is used, providing stabilization and effective heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat-resistant metallic material is used for the probe, then the probe can withstand high temperatures during friction stir welding, but the probe becomes prone to bending under external forces or moments
Solution Approach 1:
The probe is constructed as a composite structure with an inner core made of ceramic material (such as silicon nitride Si3N4 or silicon carbide SiC) that provides high bending resistance and stiffness, surrounded by an outer layer of heat-resistant metallic material (such as Inconel or Hastelloy) that provides thermal resistance. This composite design allows the probe to simultaneously withstand both high temperatures and external bending forces without deforming.
2Strength
If the probe is made thicker to counteract bending, then bending resistance improves, but the probe cannot be used for narrow welds
Solution Approach 1:
The ceramic inner core provides extremely high stiffness and bending resistance with a slender cross-section, enabling the probe to maintain structural integrity without requiring increased thickness. This allows the use of thin probes suitable for narrow welds while maintaining adequate bending resistance through the high modulus of elasticity of the ceramic material.
Solution Approach 2:
The ceramic material is concentrated in the inner core region where bending stresses are highest, providing localized reinforcement exactly where needed. The outer metallic layer provides thermal protection, creating a functionally optimized structure where each material performs its specialized function without unnecessary bulk.
3Strength
If a ceramic material is used for the probe, then bending resistance and thermal stability improve, but thermal conductivity decreases
Solution Approach 1:
The inner ceramic core provides bending resistance and thermal stability, while the outer metallic layer provides thermal conductivity. This composite structure optimizes both mechanical and thermal properties, allowing the probe to maintain its shape under load while efficiently transferring heat to the workpiece during friction stir welding.
Solution Approach 2:
Different regions of the probe are assigned different material properties: the inner core region handles mechanical loading with ceramic material, while the outer surface region handles heat transfer with metallic material. This local optimization ensures each function is performed by the most suitable material.
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 dual-material probe design enhances the tool's resistance to bending, allowing for more durable and slender probes that can produce stable welds in narrow seams while maintaining heat transfer efficiency.
Implementation Method 1
the welding tool is pressed with a rotating probe with high force between the workpieces to be joined... the area between the shoulder of the welding tool and the workpieces heats up to just below the melting point of the workpieces
Implementation Method 2
a ceramic material with high modulus of elasticity and thermal stability forms a support area
Implementation Method 3
a metallic material with high thermal conductivity and friction properties is used, providing stabilization and effective heat transfer
Data Source
Figure 1
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Figure 4~6
AI summary
The invention relates to a welding tool (10) for connecting at least two workpieces (12) by means of friction stir welding, comprising a probe (16) for applying frictional heat on the workpieces (12), wherein the probe (16) comprises a first probe region (24) formed by a first material (28) and a second probe region (26) formed by a second material (30). The invention further relates to a production method for producing such a welding tool (10).