Boron-Modified Inconel 625 Welding Material for Crack-Free Joints
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Solution Overview
Problem
Nickel-based superalloys like Inconel 625 are prone to micro cracking in the heat-affected zone during welding, limiting their use in high-temperature applications and requiring costly purification to maintain ductility, which increases production costs.
Innovation Solution
A boron-modified Inconel 625 welding material with a carbon content of 0.04 wt. % or less is developed, allowing for standard drawing and extrusion processes while producing crack-free welds with superior yield strength and ductility, suitable for turbine engine components and other alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard Inconel 625 welding material is used, then good oxidation resistance and mechanical properties are achieved, but micro cracking occurs in the heat affected zone during welding
Solution Approach 1:
The patent modifies the chemical composition parameters of Inconel 625 by adding boron (0.005-0.05 wt%) and controlling carbon content (0.03-0.10 wt%), which changes the metallurgical behavior during welding to prevent micro cracking in the heat affected zone while maintaining oxidation resistance and mechanical properties
Solution Approach 2:
The patent creates a composite alloy system by combining Inconel 625 base material with boron and controlled carbon content, where boron acts as a grain boundary modifier and carbon controls carbide formation, resulting in a material that resists both cracking and oxidation
2Ease of manufacture
If carbon content is increased to 0.06-0.1 wt. %, then ductility is maintained for standard drawing processes, but carbide formation occurs which affects weld quality
Solution Approach 1:
The patent optimizes the carbon content parameter to a specific range (0.03-0.10 wt%) and combines it with boron addition, which allows the material to maintain sufficient ductility for standard drawing processes while preventing excessive carbide formation that would degrade weld quality
Solution Approach 2:
Boron acts as an intermediary element that modifies the interaction between carbon and the nickel-chromium-molybdenum matrix, allowing carbon to remain in solid solution and prevent carbide formation while still providing the carbon needed for ductility during wire drawing
3Reliability
If boron content is increased to reduce melting temperature and prevent liquidation cracking, then weld cracking is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a narrow boron content range (0.005-0.05 wt%) that is sufficient to modify melting behavior and prevent liquidation cracking without requiring complex alloying, thereby maintaining manufacturing simplicity while achieving the desired reliability improvement
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 boron-modified welding material achieves high ductility and reduced melting temperature, enabling crack-free welds with enhanced mechanical properties, exceeding those of standard Inconel 625, and allowing for the use of standard drawing processes, reducing production costs and improving weldability.
Implementation Method 1
Modification of Inconel 625 with boron reduced melting temperature
Implementation Method 2
the content of carbon in nickel based alloy comprising of 0.4-0.6 wt. % of boron (B)... should not exceed about 0.04 wt. % to avoid or minimize formation of carbides
Implementation Method 3
IN625 produces sound welds but the heat affected zone (HAZ) of Inconel® 738, GTD 111, GTD 222, Inconel 713 and some other precipitation hardening superalloys with high content of gamma prime phase (γ′) is prone to micro cracking
Implementation Method 4
Modification of Inconel 625 with boron reduced melting temperature and liquidation cracking in the HAZ of welds
Data Source
AI summary
A ductile boron bearing nickel based welding material which includes boron within the range of 0.4-0.6 wt. % B, carbon from a trace amount to 0.04 wt. % C, 17-23 wt. % Cr, 0.35-10 wt. % Mo, 0.1-4.15 wt. % Nb with nickel or iron and impurities to balance for manufacturing of welding and brazing wires, powders and foils used in the repair of various articles made of nickel, cobalt and iron based alloys.