Metal Pipe Thickened End with Alternating Hardness Zones
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Solution Overview
Problem
Existing methods for thickening metal pipes often result in buckling when the thickness increase ratio exceeds a certain threshold, making it difficult to achieve the desired thickening without compromising structural integrity.
Innovation Solution
A metal pipe design with a thin portion and a thickened end portion, featuring a taper portion with alternating high and low hardness zones, and a manufacturing method involving axial pressing with specific die and punch configurations to prevent buckling, allowing for a thickness increase ratio of 1.2 or more without buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness increase ratio is increased to thicken the metal pipe end portion, then the strength and rigidity are improved, but buckling occurs during the thickening process
Solution Approach 1:
The thickened end portion is divided into multiple circumferential sections with alternating high hardness and low hardness zones. This segmentation allows different regions to undergo thickening at different rates, preventing uniform buckling while achieving the desired thickness increase ratio of 1.4 or more.
Solution Approach 2:
Different circumferential regions of the thickened end portion are given different local properties through alternating high and low hardness zones. The high hardness portions resist buckling while the low hardness portions allow controlled deformation, enabling overall thickening without structural failure.
2Reliability
If the thickness increase ratio is increased to thicken the metal pipe end portion, then the welding quality is improved, but it becomes difficult to perform desired thickening due to buckling
Solution Approach 1:
The end portion is segmented into alternating high and low hardness circumferential zones, allowing the thickening process to proceed without buckling even at high thickness increase ratios (1.4 or more), thereby achieving both good welding quality and manufacturability.
Solution Approach 2:
The hardness distribution parameter is changed by creating alternating high and low hardness zones in the thickened end portion. This parameter change enables the material to withstand high thickness increase ratios during manufacturing while maintaining structural integrity for quality welding.
3Weight of moving object
If the thickness of the member is increased only in the portion where welding is performed, then the weight of the part is reduced, but buckling occurs during the thickening process
Solution Approach 1:
The localized thickened end portion is divided into alternating high and low hardness circumferential zones, enabling weight reduction through selective thickening while preventing buckling during the thickening process by allowing controlled differential deformation.
Solution Approach 2:
Different circumferential regions within the thickened end portion have different local hardness properties, allowing the structure to accommodate localized thickening for weight savings while the alternating hardness pattern prevents buckling during manufacturing.
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
The solution enables the creation of metal pipes with thickened ends that maintain structural integrity and prevent buckling, even at high thickness increase ratios, enhancing their strength and fatigue life for applications like automobile parts.
Implementation Method 1
in upsetting processing which is performed in the related art, the thickness of a portion of a metal pipe in a longitudinal direction is increased by applying a pressure to the metal pipe in the longitudinal direction
Data Source
AI summary
A metal pipe having a thickened end portion, the metal pipe includes: when viewed in a longitudinal direction of the metal pipe, a thin portion which has a thickness t0; a first thickened portion which is provided on one end and has a thickness T which is larger than the thickness t0; and a first taper portion which is provided between the thin portion and the first thickened portion and has the thickness which gradually increases from t0 to T; when a hardness of an inner surface of the first thickened portion is measured in a circumferential direction and the hardness is plotted with respect to a position in the circumferential direction, in which a waveform representing a high hardness portion having a hardness which is 95% or more of a maximum hardness in the circumferential direction and a waveform representing a low hardness portion having a hardness which is less than 95% of the maximum hardness alternately appear, and a plurality of combinations of the waveform representing the high hardness portion and the waveform representing the low hardness portion appear.