Metal Pipe Flange Hardness Control for Easier Welding
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Solution Overview
Problem
Existing forming devices face difficulties in welding metal pipes with flange portions due to high hardness, which makes it challenging to apply pressure during the welding process without compromising the strength of the pipe portion.
Innovation Solution
A forming device and method that incorporate a hardness lowering portion, utilizing temperature control or cooling mechanisms to reduce the hardness of the flange portion below that of the pipe portion, ensuring easy welding while maintaining the pipe's strength, by using temperature control portions to extend the cooling time and decrease hardenability at the flange surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the metal pipe material is expanded using a forming die to create a flange portion, then the pipe structure is formed, but the hardness of the flange portion becomes excessively high making welding difficult
Solution Approach 1:
The invention applies different cooling conditions to different regions of the forming die. The pipe forming surface maintains standard cooling to preserve high hardness and strength, while the flange forming surface uses controlled cooling (either reduced cooling rate or delayed cooling timing) to achieve lower hardness for easier welding. This local differentiation of cooling quality resolves the contradiction between needing high strength in the pipe portion and ease of welding in the flange portion.
Solution Approach 2:
The invention implements preliminary cooling control before the expansion process completes. By adjusting the cooling timing and rate during the forming process itself, the flange portion is prepared in advance with appropriate hardness characteristics. This preliminary action allows the flange to be formed with lower hardness while the pipe portion maintains high strength, enabling subsequent welding without compromising overall structural integrity.
2Reliability
If excessive pressure is applied during welding of the flange portion, then welding can be achieved, but dust generation and uneven welding quality occur
Solution Approach 1:
The invention changes the physical parameter of hardness in the flange portion by controlling cooling conditions during formation. By reducing the hardness of the flange portion through adjusted cooling rates or timing, the material becomes more ductile and easier to deform during welding. This parameter change eliminates the need for excessive welding pressure, thereby preventing dust generation and ensuring uniform welding quality without compromising the reliability of the weld joint.
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
Enables easy welding of the flange portion against another member while ensuring the pipe portion's high strength, reducing the need for excessive pressure and minimizing issues like dust generation and uneven welding quality.
Implementation Method 1
temperature control portions that make a temperature of the flange forming surfaces at the time of formation higher than temperatures of the pipe forming surfaces
Implementation Method 2
extend the cooling time and decrease hardenability at the flange surfaces
Implementation Method 3
hardness lowering portion which lowers a hardness of the flange portion to be lower than a hardness of the pipe portion
Data Source
AI summary
A forming device which expands a metal pipe material to form a metal pipe having a pipe portion and a flange portion includes a hardness lowering portion which lowers a hardness of the flange portion to be lower than a hardness of the pipe portion.