Curved Tungsten Alloy Suture Needles Heat Treatment
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Solution Overview
Problem
Curved tungsten alloy suture needles often exhibit reduced bending stiffness due to stresses imparted during the curving process, leading to limited plastic deformation and poor penetration control during surgical procedures, especially in calcified tissues.
Innovation Solution
Heat treating the curved tungsten alloy suture needles below the recrystallization temperature, typically between 700°C to 1900°C, to enhance their bending stiffness and strength, while maintaining ductility, thereby improving their ability to resist elastic deflection and maintain shape under deforming forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If curved tungsten alloy suture needles are used, then penetration performance is improved, but bending stiffness is reduced due to stresses from the curving process
Solution Approach 1:
The patent applies heat treatment to change the physical parameters of the tungsten alloy needle, specifically heating to temperatures between 700-1900°C to modify the microstructure and eliminate residual stresses from curving, thereby restoring bending stiffness while maintaining the curved geometry needed for penetration performance
Solution Approach 2:
The heat treatment is applied as a preliminary action after needle curving but before surgical use, pre-restoring the bending stiffness properties so that the needle is ready for optimal performance during the actual surgical procedure without requiring additional treatment at the time of use
2Strength
If heat treatment is applied to enhance bending stiffness, then strength is improved, but ductility may be compromised
Solution Approach 1:
The patent carefully controls the heat treatment parameters (temperature range of 700-1900°C, heating duration, and cooling rate) to achieve the desired balance between bending stiffness and ductility, using parameter optimization to prevent excessive grain growth or phase transformations that would compromise ductility while still eliminating residual stresses
Solution Approach 2:
The patent uses tungsten alloy compositions (such as tungsten with rhenium, osmium, tantalum, or molybdenum) that inherently provide both strength and ductility, and the heat treatment further optimizes the microstructure of this composite alloy system to achieve the desired property balance
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 heat-treated tungsten alloy suture needles demonstrate significantly improved bending stiffness and strength, as evidenced by increased yield bend moment and reduced elastic bending, enhancing control and performance during surgical procedures without compromising ductility.
Implementation Method 1
heat treating the curved tungsten alloy suture needles below the recrystallization temperature, typically between 700°C to 1900°C, to enhance their bending stiffness and strength
Data Source
AI summary
A method for making a curved tungsten alloy suture needle comprising the step of heating tungsten alloy needle blanks or a tungsten alloy suture needle to a temperature below the recrystallization temperature of the alloy. The tungsten alloy suture needles described herein have a desirable combination of stiffness, strength, ductility, and surface color.