Dissimilar Alloy Stud Welding Using a Hardened Body and Weldable Tip
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dissimilar metal alloys used in aircraft components cannot be effectively welded in a hardened state, posing challenges for joining these materials.
Innovation Solution
A system comprising a hardened stud body made from an austenitic nickel-chromium-based alloy (INCONEL 718) and an unhardened stud subunit made from another alloy (INCONEL 625) is created, where the unhardened stud body is heat-treated to become hardened, and then welded to a substrate using methods like friction welding or capacitor discharge welding, focusing the weld on the unhardened subunit to achieve a strong and durable bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dissimilar metal alloys are welded in a hardened state, then the strength and durability of the weld is improved, but the weldability and ease of manufacture deteriorates
Solution Approach 1:
The stud is divided into two distinct portions: a hardened stud body portion made from Inconel 718 alloy and an unhardened stud subunit portion made from Inconel 625 alloy. This segmentation allows each portion to have optimized properties - the hardened body provides strength while the unhardened subunit provides weldability.
Solution Approach 2:
Different regions of the stud have different material properties. The stud body portion is hardened for strength, while the stud subunit portion remains unhardened for ease of welding. This local differentiation of material properties resolves the contradiction between needing hardness for strength and needing softness for weldability.
2Strength
If the stud body is heat treated to become hardened, then the mechanical strength is improved, but the ability to weld deteriorates
Solution Approach 1:
The stud is divided into two distinct portions: a hardened stud body portion made from Inconel 718 alloy and an unhardened stud subunit portion made from Inconel 625 alloy. This segmentation allows each portion to have optimized properties - the hardened body provides strength while the unhardened subunit provides weldability.
Solution Approach 2:
Different regions of the stud have different material properties. The stud body portion is hardened for strength, while the stud subunit portion remains unhardened for ease of welding. This local differentiation of material properties resolves the contradiction between needing hardness for strength and needing softness for weldability.
3Reliability
If dissimilar materials are coupled to achieve hardened properties, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Two different Inconel alloys (718 and 625) are joined together in a single stud component to combine the advantages of both materials - the high strength of hardened Inconel 718 and the excellent weldability of Inconel 625, creating a unified structure that achieves both reliability and manufacturability.
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 approach allows for the creation of a structure with the benefits of hardened material properties while maintaining a strong and durable weld, overcoming the difficulty of welding hardened materials to unhardened substrates.
Implementation Method 1
The unhardened stud body may undergo a heat treatment to become the hardened stud body
Implementation Method 2
The unhardened stud subunit may be at least one of friction welded, inertia bonded, explosive welded, resistance welded, laser welded, gas tungsten arc welded, or brazed to an unhardened stud body
Implementation Method 3
The welding the stud to the substrate may comprise capacitor discharge welding
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system is provided comprising a hardened stud body (102) and an unhardened stud subunit (104) coupled to the hardened stud body (102). The hardened stud body (102) may comprise a first composition having by weight between 17% and 21% chromium, between 2.8% and 3.3% molybdenum, between 50% to 55% nickel, and between 4.75% and 5.5% niobium. The unhardened stud subunit (104) may comprise a second composition having by weight between 20% and 23% chromium, between 8% and 10% molybdenum, at least 58% nickel, and between 3.15% and 4.15% niobium.