Linear Friction Welding Pressure Control for Lower Joint Temperature
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Solution Overview
Problem
Conventional linear friction welding methods struggle with inaccurate control of welding temperature and excessive softening at the joint interface, leading to difficulties in setting desired welding conditions and potential deterioration of mechanical properties.
Innovation Solution
The method controls welding temperature by setting the pressure during linear friction welding to be between the yield stress and tensile strength of the materials, ensuring accurate discharge of softened material as a flash, thereby maintaining the welding temperature at a desired level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If friction welding is performed by repeatedly moving one member on the same trajectory while contacting the other member, then the welding process can be controlled by stop means, but the period from stop command generation to actual stopping cannot be sufficiently shortened to control welding temperature
Solution Approach 1:
The patent applies preliminary action by pre-positioning the stop command at specific locations along the welding trajectory. The stop positions are predetermined based on the desired welding temperature and material properties, allowing the system to execute the stop command at the optimal moment without delay. This preliminary planning of stop positions enables precise temperature control by ensuring the welding process is interrupted exactly when the target temperature is reached.
2Manufacturing precision
If conventional linear friction welding is performed, then a softened flash is discharged from the welding interface to form a new surface, but the welding temperature cannot be accurately set or lowered
Solution Approach 1:
The patent applies parameter changes by systematically varying multiple welding parameters including welding speed, applied pressure, and stop position along the trajectory. By adjusting these parameters in combination, the welding temperature can be precisely controlled and lowered to the desired level. The stop position parameter is particularly critical, as it determines the total friction heating duration and thus the final welding temperature.
Solution Approach 2:
The patent applies periodic action through the repeated back-and-forth linear movement of one member along the same trajectory. This periodic frictional contact generates controlled heating cycles, allowing the welding interface to reach the desired temperature through cumulative friction heat while enabling precise interruption at predetermined stop positions.
3Ease of manufacture
If friction welding is performed with repeated linear movement, then the welding mechanism is not fully understood and welding conditions must be optimized through extensive preliminary tests
Solution Approach 1:
The patent applies self-service by designing a system where the welding process automatically controls its own temperature through the predetermined stop positions and friction heating mechanism. The repeated linear movement and controlled stopping create a self-regulating welding process that reduces dependency on extensive preliminary testing, as the stop positions can be calculated based on material properties and desired welding parameters.
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
Accurate control of welding temperature is achieved, reducing the temperature and preventing mechanical property deterioration, while suppressing the formation of brittle martensite and ensuring a strong, tough welded joint.
Implementation Method 1
linear friction welding in which metal members are slid in a linear locus... frictional heat generated by sliding between the materials to be welded
Implementation Method 2
a pressure applied substantially perpendicular to the interface to be welded
Data Source
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AI summary
A linear friction welding method capable of accurately controlling a welding temperature and capable of lowering the welding temperature is provided. The present invention is a linear friction welding method comprising: a first step of forming a welded interface by bringing one member into contact with the other member; a second step of repeatedly sliding one member and the other member on the same locus and discharging flash from the welded interface in a state where pressure is applied substantially perpendicularly to the welded interface; and a third step of forming a welded surface by stopping the sliding and setting the pressure to be not less than the yield stress and not more than the tensile strength of one member and/or the other member at a desired welding temperature.