Welding Stud With Composite Shaft And Aluminum Head
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Solution Overview
Problem
Existing welding studs made of lightweight materials, such as aluminum alloys, face issues with strength, corrosion, and unreliable connections, particularly under vibrating loads, when combined with steel using friction welding, which limits their application in lightweight constructions.
Innovation Solution
A welding stud comprising a welding part and a shaft made of different materials, connected through a shrinking process where the welding part is heated to expand and fit around the shaft, with an optional auxiliary medium like solder for improved corrosion protection and sealing, ensuring a secure and robust connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If friction welding is used to connect lightweight material (aluminum alloy) and steel, then the welding stud can be assembled to different components, but the connection becomes brittle and unreliable under vibrating load due to intermetallic phase seams
Solution Approach 1:
A transition piece made of intermediate material (e.g., steel or aluminum alloy) is introduced between the aluminum alloy welding portion and the steel shaft. This intermediary component prevents direct contact between dissimilar metals, eliminating intermetallic phase formation while maintaining mechanical and electrical connection properties.
Solution Approach 2:
The welding stud employs a composite structure with three distinct material zones: aluminum alloy welding portion, intermediate transition piece, and steel shaft. This composite construction allows each material to perform its optimal function while avoiding harmful material interactions at the interfaces.
2Ease of manufacture
If friction welding is used to connect aluminum alloy and steel, then the welding stud can be manufactured, but corrosion risk increases due to galvanic corrosion between dissimilar metals
Solution Approach 1:
The intermediate piece acts as a galvanic isolation barrier between aluminum alloy and steel, preventing direct electrochemical contact. This eliminates the galvanic cell formation that would otherwise occur between the two dissimilar metals, thereby preventing corrosion.
3Adaptability or versatility
If friction welding is used to connect welding portion and shaft, then the welding stud can be assembled, but the connection is brittle and contact is not always secured
Solution Approach 1:
The connection is divided into three segmented portions: welding portion, intermediate piece, and shaft. Each segment can be independently optimized for its specific function, and the segmentation allows for controlled interference fits and mechanical interlocking at each interface, enhancing overall connection strength.
4Weight of moving object
If lightweight material (aluminum alloy) is used for the welding portion, then the welding stud weight is reduced, but the strength and torque capacity are compromised
Solution Approach 1:
Different parts of the welding stud have different material properties optimized for their specific functions: the welding portion uses lightweight aluminum alloy for weight reduction, while the shaft uses high-strength steel for torque capacity. The intermediate piece bridges these local quality requirements.
Solution Approach 2:
The welding stud is constructed as a composite assembly with aluminum alloy for the welding portion (prioritizing weight reduction) and steel for the shaft (prioritizing strength), connected through an intermediate piece that maintains the mechanical integrity required for torque transmission.
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 lightweight, corrosion-resistant welding stud with enhanced strength and sealing, capable of withstanding varying loads and allowing for diverse cross-sectional designs without compromising torque, while being easy to manufacture and implement.
Implementation Method 1
heating the welding part such that the area surrounding the recess is dilated and the first recess dimension is increased
Implementation Method 2
cooling the first end portion of the shaft; fitting the first end portion in the recess; Shrinking the welding part around the first end portion
Data Source
Figure 1~2
AI summary
Method for the manufacture of a welding stud (10) and welding stud (10) comprising a welding part (12) adapted to be welded to a workpiece, the welding part comprising a recess (22), the welding part being in a first material, and a shaft (14) extending along a longitudinal axis between a first end portion and a second end portion, the first end portion being inserted into the recess, wherein the shaft is in a second material, different from the first material, wherein the welding part and the shaft are connected together by shrinking of the welding part (12) around the first end portion.