Friction Welding Pressure Staging for Lower-Temperature Defect-Free Joints
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Solution Overview
Problem
Existing friction welding methods struggle to accurately control welding temperature and prevent defects across various materials, particularly in high tensile strength steel and high carbon steel, leading to limited material composition and increased hardness in the heat-affected zone.
Innovation Solution
The method involves controlling welding temperature by adjusting pressure at the welding interface, with a two-step process where initial high pressure lowers temperature and subsequent pressure reduction ensures uniformity, utilizing yield stress and tensile strength limits to manage friction heat and prevent unwelded areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional friction welding methods are used to join high tensile strength steel or high carbon steel, then welding can be achieved, but the welding temperature cannot be accurately controlled and the heat-affected zone exhibits excessive hardness increase
Solution Approach 1:
The patent applies dynamics by implementing a two-stage pressure control system where the welding pressure is dynamically adjusted during the friction welding process. In the first stage, high pressure is applied to suppress excessive welding temperature and prevent martensite formation. In the second stage, pressure is reduced to enable proper welding. This dynamic pressure adjustment allows accurate control of welding temperature throughout the process.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the welding pressure parameter during the friction welding process. The pressure is changed from a high initial value to a lower final value, and rotation speed is also adjusted between stages. These parameter changes enable precise control of friction heat generation and welding temperature, preventing excessive hardness in the heat-affected zone while ensuring proper welding.
2Temperature
If high pressure is applied during friction welding to control temperature, then welding temperature is suppressed, but uniform temperature distribution across the welding interface becomes difficult to achieve
Solution Approach 1:
The patent applies dynamics by implementing a two-stage pressure control system where the welding pressure is dynamically adjusted during the friction welding process. In the first stage, high pressure is applied to suppress excessive welding temperature and prevent martensite formation. In the second stage, pressure is reduced to enable proper welding. This dynamic pressure adjustment allows accurate control of welding temperature throughout the process.
Solution Approach 2:
The patent utilizes periodic action by dividing the friction welding process into distinct stages with different pressure conditions. The first stage operates under high pressure for a specific period to control temperature, then transitions to a second stage with reduced pressure. This periodic variation in pressure conditions enables both temperature suppression and uniform temperature distribution across the welding interface.
3Strength
If friction welding is performed on high carbon steel or high tensile strength steel, then welding of strong materials is achieved, but the material composition range is limited and hardness increases in the joint portion
Solution Approach 1:
The patent applies dynamics by implementing a two-stage pressure control system where the welding pressure is dynamically adjusted during the friction welding process. In the first stage, high pressure is applied to suppress excessive welding temperature and prevent martensite formation. In the second stage, pressure is reduced to enable proper welding. This dynamic pressure adjustment allows accurate control of welding temperature throughout the process.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the welding pressure parameter during the friction welding process. The pressure is changed from a high initial value to a lower final value, and rotation speed is also adjusted between stages. These parameter changes enable precise control of friction heat generation and welding temperature, preventing excessive hardness in the heat-affected zone while ensuring proper welding.
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 precise temperature control and defect-free welding across different materials, reducing hardness in the heat-affected zone and maintaining mechanical properties, even at lower welding temperatures.
Implementation Method 1
a friction welding method in which one member (2) and the other member (4) are rotationally slid while a load is applied substantially perpendicularly to an interface (6) to be welded
Data Source
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AI summary
The present invention provides a friction welding method capable of reducing the welding temperature in addition to accurately controlling the welding temperature, and a friction welding method capable of obtaining a welded portion free of defects regardless of the type of the material to be welded, and a welded structure obtained by the friction welding method. A frictional welding method in which one member is brought into contact with the other member and slides while a load is applied substantially perpendicularly to the interface to be welded, the frictional welding method comprising: a first step in which frictional welding is carried out by setting a pressure (P1) calculated from the area and the load of the interface to be welded to be equal to or higher than the yield stress and the tensile strength of one member and/or the other member at a desired welding temperature; and a second step in which frictional welding is carried out by lowering the load, wherein the first step and the second step are continuously carried out.