Double-Sided Friction Stir Welding Tool Without a Probe
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Solution Overview
Problem
The existing friction stir welding methods face challenges in achieving uniform plastic flow and high welding speed for structural steel, leading to defects and reduced tool durability, particularly due to insufficient temperature rise and shearing stress in the thickness direction of metal plates.
Innovation Solution
The development of rotating tools for double-sided friction stir welding, featuring end portions with circular and convex or concave curved shapes, and vortex-shaped stepped portions, which rotate in opposite directions, ensuring adequate diameter and angle settings to facilitate uniform plastic flow and stress distribution, eliminating the need for a probe and enhancing tool durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotating tool with a probe is used for friction stir welding, then welding can be performed on metal plates, but the probe is prone to breakage and wear due to high stress, reducing tool durability
Solution Approach 1:
The invention removes the probe component from the rotating tool, retaining only the shoulder portion. This extraction eliminates the weak point (probe) that was prone to breakage and wear, thereby improving tool durability while maintaining the welding function through the shoulder portion alone
Solution Approach 2:
The invention changes the geometric parameters of the rotating tool by modifying the end portion shape to convex curved, concave curved, or planar forms with specific diameter ratios. These parameter changes optimize stress distribution and material flow, enabling the tool to withstand welding stresses without probe breakage
2Productivity
If welding speed is increased to improve productivity, then output increases, but defects occur in the welded portion due to insufficient temperature rise and plastic flow
Solution Approach 1:
The invention applies curved surface geometry to the end portion of the rotating tool (convex or concave curvature). This curvature optimizes the contact area and pressure distribution during welding, enhancing material flow and temperature generation even at high welding speeds, thereby preventing defects while maintaining productivity
Solution Approach 2:
The invention optimizes the diameter of the rotating tool end portion relative to the metal plate thickness (specific diameter ratios). This parameter optimization ensures sufficient temperature rise and plastic flow throughout the plate thickness, enabling defect-free welding at high speeds
3Ease of manufacture
If the rotating tool end portion is made with a simple planar shape, then manufacturing is easy, but uniform plastic flow in the thickness direction of metal plates cannot be achieved
Solution Approach 1:
The invention transitions from a simple planar end portion to curved surfaces (convex or concave). This geometric modification improves material flow uniformity across the plate thickness by optimizing contact pressure distribution, while the curvature can be achieved through relatively simple manufacturing processes, balancing manufacturability with performance
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 enables the achievement of defect-free joints with sufficient strength and increased welding speed, while improving the durability of the rotating tools by uniformly distributing temperature and stress, thus making double-sided friction stir welding more practical for structural steel.
Implementation Method 1
heat generated between a rotating tool and the metal plates and plastic flow by inserting the rotating tool
Implementation Method 2
shearing stress applied as a load thereto during welding
Data Source
AI summary
Disclosed are rotating tools for double-sided friction stir welding that are applied to double-sided friction stir welding, which is a technique for welding two metal plates by rotating a pair of rotating tools, which oppose each other, in opposite directions, a double-sided friction stir welding apparatus that uses the rotating tools, and a double-sided friction stir welding method. A pair of rotating tools for double-sided friction stir welding that are used in double-sided friction stir welding, which is a technique for welding metal plates by using a pair of rotating tools that are each disposed on one of first and second surfaces of an unwelded portion of the metal plates such that the rotating tools rotate in opposite directions, include end portions each of which is formed in a circular and planar shape. The end portions are each made of a material harder than the metal plates.