Medical Guide Wire Welding Strength Using Eutectic Alloy
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Solution Overview
Problem
Existing medical guide wires lack sufficient tensile and welding strength at the welded portion between the core wire and the helical spring body, particularly when using austenitic stainless steel, and do not effectively utilize the thermal influence for enhanced mechanical properties.
Innovation Solution
A medical guide wire design featuring a core wire made of austenitic stainless steel treated with a solid solution process and drawn with a cross-sectional reduction ratio of 80%-97.6%, combined with a eutectic alloy welding member having a melting temperature range of 180° C. to 495° C., which improves tensile and welding strength by utilizing the melting heat for secure bonding and enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the core wire is made of austenitic stainless steel and welded using conventional brazing procedures, then the welding process is simple, but the tensile strength and welding strength at the welded portion are insufficient
Solution Approach 1:
The patent applies parameter changes by controlling the cross-sectional reduction ratio during wire drawing to 80%-97.6% and selecting specific austenitic stainless steel compositions (containing Ni: 8-16%, Cr: 16-20%, C: 0.03-0.10%). These parameter optimizations enhance the core wire's base strength before welding, allowing the welded portion to achieve sufficient tensile strength without complex welding procedures.
Solution Approach 2:
The patent implements preliminary action by pre-treating the core wire through solid solution treatment and controlled drawing processes before welding. This preliminary strengthening of the core wire ensures that when welding occurs, the overall assembled strength (core wire + welding portion) achieves the required tensile strength without requiring overly complex welding procedures.
2Strength
If the core wire is drawn with high cross-sectional reduction ratio to improve tensile strength, then the tensile strength increases, but the thermal influence during welding may deteriorate mechanical strength
Solution Approach 1:
The patent resolves this contradiction through precise parameter control: limiting the cross-sectional reduction ratio to 80%-97.6% and specifying austenitic stainless steel composition ranges. These parameters are optimized to achieve high tensile strength while maintaining thermal stability during welding, preventing deterioration of mechanical properties under thermal influence.
Solution Approach 2:
The patent uses composite material strategy by combining austenitic stainless steel with specific alloying elements (Ni, Cr, C within defined ranges) to create a core wire that possesses both high tensile strength and thermal resistance. This composite approach ensures the wire maintains mechanical strength even when subjected to welding thermal influence.
3Strength
If the welding member is used simply as a securement means, then the assembly is simple, but the welding strength and mechanical integrity are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the welding member's material composition and geometric parameters. The welding member is designed with specific dimensions and material properties that enable it to provide sufficient welding strength and mechanical integrity while maintaining a relatively simple structure, avoiding excessive complexity.
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 significantly enhances the tensile strength and welding strength at the welded portion, ensuring the guide wire's safety and reliability by improving the wetting properties and mechanical integrity, while maintaining visibility and corrosive resistance.
Implementation Method 1
The welding member is represented by a eutectic alloy having a melting temperature ranging from 180° C. to 495° C.
Implementation Method 2
The core wire and the helical spring body are partly welded with the use of a welding member
Implementation Method 3
The core wire is made of austenitic stainless steel wire treated with a solid solution procedure
Data Source
AI summary
In a medical guide wire 1, a flexible core wire 2 is made of austenitic stainless steel wire treated with a solid solution procedure, and drawn with a whole cross sectional reduction ratio as 80%-97.6%. The core wire 2 and a helical spring body 3 are welded by a welding member 4. The welding member 4 is made of eutectic alloy having a melting temperature ranging from 180° C.-495° C. Upon welding the helical spring body 3 to the core wire 2 which is made of the stainless steel metal, the procedure prevents the medical guide wire 1 from sacrificing its mechanical strength by significantly reducing the thermal influence on the core wire 2 and the helical spring body 3.