Modular Hot Gas Component Joining for Crack-Resistant Superalloys
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Solution Overview
Problem
Existing methods for joining nickel-based superalloy components in hot gas components, such as turbine blades, face challenges in achieving strong and stress-resistant connections without complex device requirements, particularly in regions like the tip and root of the blade.
Innovation Solution
A method involving preheating pins between airfoil and outer platforms using defocused laser radiation, followed by laser beam welding and high-temperature soldering, which reduces susceptibility to hot cracking and eliminates the need for tacking, allowing for a secure and stress-resistant joint without complex device positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding methods are used to join nickel-based superalloy segments, then strong connections can be achieved, but the susceptibility to hot cracking increases and tacking is required
Solution Approach 1:
The method applies preliminary preheating to the segments before welding to reduce thermal gradients and prevent hot cracking. The segments are heated to a controlled temperature range prior to the welding process, which eliminates the need for tacking and reduces cracking susceptibility while maintaining connection strength
Solution Approach 2:
The invention changes the thermal parameters by implementing controlled preheating and using defocused laser radiation with specific power densities. This parameter modification allows direct welding without tacking and reduces hot cracking while achieving strong connections in nickel-based superalloys
2Manufacturing precision
If high-temperature soldering is performed with precise positioning devices, then accurate segment alignment is achieved, but device complexity increases
Solution Approach 1:
The method employs self-aligning features where pins with bores automatically position segments relative to each other during the joining process. This self-service positioning mechanism eliminates the need for complex external positioning devices while maintaining accurate segment alignment during high-temperature soldering
Solution Approach 2:
The invention replaces complex mechanical positioning systems with a simpler pin-and-bore mechanical feature system. The pins insert into bores to provide automatic alignment, substituting elaborate positioning machinery with basic geometric features that achieve the same alignment function
3Reliability
If defocused laser radiation is used for preheating, then hot cracking susceptibility is reduced and tacking is eliminated, but energy distribution becomes less concentrated
Solution Approach 1:
The method applies defocused laser radiation to create a specific energy distribution pattern where the energy is spread over a larger area for preheating. This local quality change in energy distribution reduces hot cracking by preventing excessive heat concentration in any single point, while still achieving the necessary preheating effect
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
This method enables the creation of components that can withstand high thermal-mechanical stresses and facilitates high-temperature soldering without the need for intricate device setups, ensuring robust and reliable connections in hot gas components.
Implementation Method 1
preheating pins between airfoil and outer platforms using defocused laser radiation
Implementation Method 2
followed by laser beam welding
Implementation Method 3
high-temperature soldering
Data Source
AI summary
A method for joining a modular hot gas component by welding and high-temperature soldering. In order to optimally join high-temperature components, a first component is plugged into pins of a second component, a soldering material is placed between the two components, and the pins of the second component are welded to the first component.