Insulated Braze Joint Solidification for Defect-Free Repairs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional braze processes for metal alloys, such as those used in rotary machines, often result in solidification defects like porosity and hot cracking due to differential cooling and solidification shrinkage, which reduce the tensile strength and creep life of braze joints, leading to increased wear and potential component failure.
Innovation Solution
A system and method for creating braze joints that involves a component with a recess and a cap of braze material, where a thermal insulation layer is applied to the exposed braze surface and heat is extracted from a location closer to the inner edge of the recess than the cap, controlling the cooling process to minimize solidification defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If conventional braze processes are used to repair cracks or defects in metal alloys, then the defect can be filled and the component can be salvaged, but solidification defects such as porosity and hot cracking occur due to differential cooling and solidification shrinkage, reducing tensile strength and creep life
Solution Approach 1:
The patent applies parameter changes by modifying the thermal parameters during the braze process. Specifically, it controls the cooling rate and temperature gradient through regulated heating and cooling cycles, transforming the thermal parameters to prevent solidification defects while maintaining the ability to repair cracks and defects in metal alloys
Solution Approach 2:
The patent implements preliminary action by pre-heating the component and braze material to controlled temperatures before initiating the filling process. This preliminary thermal preparation ensures uniform temperature distribution and prevents thermal shock, thereby avoiding hot cracking and porosity formation while enabling effective defect repair
2Productivity
If the braze material is allowed to cool naturally after filling the defect, then the braze joint solidifies, but differential cooling causes the braze material closer to the surface to cool faster than deeper material, inducing solidification defects like porosity and hot cracking
Solution Approach 1:
The patent applies dynamics by implementing a dynamic cooling control system that adjusts cooling rates at different locations and times. The system transitions from rapid initial cooling to controlled slower cooling, dynamically managing the thermal field to achieve uniform solidification while maintaining high productivity in the braze repair process
Solution Approach 2:
The patent implements feedback control by monitoring temperature distribution during the cooling process and adjusting cooling parameters accordingly. This feedback mechanism ensures uniform solidification by compensating for differential cooling rates, preventing solidification defects while maintaining efficient production cycles
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 approach reduces or eliminates solidification defects in the braze joint, enhancing its tensile strength and creep life, thereby increasing the longevity and reliability of components subjected to high thermal and mechanical stresses.
Implementation Method 1
an insulation layer that at least partially covers the exposed braze surface
Implementation Method 2
heating the furnace to a target temperature so that the braze material becomes molten or partially molten, allowing the braze material to flow into the spaces that form the defect
Implementation Method 3
as the braze material begins to cool after the braze material has filled the defect in the component, solidification shrinkage occurs within the joint
Data Source
AI summary
A system for creating a braze joint within a component. The system includes an environment operable to reach a braze temperature sufficient to melt at least a portion of a braze material. The system also includes a component within the environment, the component including a base having a base surface, a recess depending from the base surface into the base to an inner edge, and a braze material within the recess and forming a cap above the base surface. The braze material fills the recess from the cap to the inner edge. The cap has an exposed braze surface. The system also includes an insulation layer that at least partially covers the exposed braze surface.