Solid-State Pipe Joining With Directed Burr Flow
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Solution Overview
Problem
Solid-state joining methods like friction welding and linear friction welding face challenges in controlling the shape and burr formation at the joined interface, particularly in pipe materials, leading to reduced mechanical properties and unsuitable use in gas or liquid circulation applications.
Innovation Solution
A method that involves controlling the discharge direction of burrs by shaping the end surfaces of the materials to be joined, using external heating to elevate temperature, and applying pressure to deform the interface, with a gradient on one side to suppress burr discharge, ensuring precise control over the joining process and resulting structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid-state joining methods like friction welding or linear friction welding are used to join metal materials, then the decrease in strength at the joined portion is reduced compared to melt welding, but the shape and burr formation at the joined interface cannot be controlled, particularly in pipe materials
Solution Approach 1:
The end surfaces of the pipe materials are preliminarily shaped with a specific gradient (tapered profile) before the joining process. This preliminary shaping enables control over burr discharge direction during friction welding or linear friction welding, allowing burrs to be directed outward rather than inward, thus maintaining pipe inner diameter while achieving strong joints
2Strength
If friction pressure welding is performed on high tensile steel with low carbon content to suppress hardening, then the tensile strength can be maintained at 60 kgf/mm² or above, but the crystal grain coarsens at rapid heating and transforms to hard martensite phase at rapid cooling
Solution Approach 1:
The patent modifies the material composition by adding specific alloying elements (Ti: 0.003-0.03 wt%, V: 0.003-0.03 wt%, Nb: 0.003-0.03 wt%, or Ta: 0.003-0.03 wt%) to the high tensile steel with controlled carbon content (0.05-0.1 wt%). These compositional parameter changes enable the steel to maintain high tensile strength (≥60 kgf/mm²) while suppressing excessive hardness increase and martensite formation during friction pressure welding
3Manufacturing precision
If the plate thickness of the end portion is reduced with a gradient to control burr discharge direction, then the discharge direction of burrs can be controlled and inner diameter maintained, but the device complexity increases
Solution Approach 1:
The end surface of the pipe material is segmented into zones with different thicknesses, creating a gradient structure where the plate thickness gradually decreases from the base toward the end surface. This segmentation approach controls burr discharge direction by providing a preferential path for material flow during joining, while the gradient geometry itself serves as the control mechanism without requiring additional complex devices
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 approach allows for effective control of burr discharge direction, maintaining the inner diameter of pipe materials within 20% change, achieving strong and shaped joints with improved mechanical properties, suitable for various metal materials including pipes.
Implementation Method 1
a second step for elevating a temperature in the vicinity of the interface to be joined by using external heating means
Implementation Method 2
a third step for plastically deforming the interface to be joined to discharge burrs and form a solid-state joined interface
Implementation Method 3
the friction welding (FW: Friction Welding), in which cylindrical metal members are rotated and slid together
Implementation Method 4
the linear friction welding (LFW: Linear Friction Welding), in which metal members are slid together in a linear trajectory
Data Source
AI summary
Provided are: a solid-state joining method with which it is possible to control the discharge direction of burrs and to realize sufficient joining strength; a solid-state joined joint and a solid-state joined structure that are obtained through the solid-state joining method; and a solid-state joining device that can be suitably used in the solid-state joining method. A solid-state joining method characterized by having a first step for bringing end parts of one material being joined and another material being joined into butting contact with one another and forming a joining interface, a second step for increasing the temperature in the vicinity of the joining interface by using an external heating means, and a third step for plastically deforming the joining interface to thereby discharge burrs and form a solid-state joined interface, the plate thickness of the end part of the one material being joined and/or the other material being joined is reduced, and the solid-state joining method having a gradient such that the plate thickness decreases on a side where discharge of the burrs is suppressed.