Power Beam Welding of Ni-Based Superalloys to Prevent Cracking
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Solution Overview
Problem
Precipitation-hardened superalloys, particularly Ni-based superalloys, are difficult to weld due to susceptibility to cracking during welding and post-weld heat treatment, and conventional techniques require pre-weld heat treatments that increase complexity and time.
Innovation Solution
A method and system for welding precipitation-hardened superalloys using a power beam that is oscillated longitudinally to uniformly heat and melt the material, followed by gradual intensity reduction during solidification, eliminating pre-weld treatments and reducing cooling rates to minimize lattice misfit and internal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-weld overageing treatment is applied to precipitation-hardened superalloys, then ductility is improved and cracking susceptibility is reduced, but process complexity and manufacturing time increase
Solution Approach 1:
The patent applies preliminary action by performing pre-weld overageing treatment before welding to grow coarse gamma prime particles in advance. This preliminary microstructural modification increases ductility and reduces cracking susceptibility during the subsequent welding process, directly addressing the reliability improvement while accepting the necessary process complexity
Solution Approach 2:
The patent utilizes parameter changes by controlling the heat treatment temperature and time parameters during pre-weld overageing to achieve specific gamma prime particle sizes. By optimizing these parameters, the material microstructure is modified to reduce lattice misfit and improve crack resistance, balancing reliability enhancement with process efficiency
2Reliability
If pre-weld overageing treatment is applied to precipitation-hardened superalloys, then ductility is improved and cracking susceptibility is reduced, but manufacturing time increases
Solution Approach 1:
The pre-weld overageing treatment is performed as a preliminary action before welding to establish a crack-resistant microstructure in advance. This allows the welding process to proceed without interruptions or rework due to cracking, potentially reducing total manufacturing time despite the added heat treatment step
Solution Approach 2:
By optimizing the temperature and time parameters of the pre-weld overageing treatment, the patent achieves the necessary microstructural changes in the shortest possible time. The parameters are tuned to grow sufficient gamma prime particles without excessive treatment duration, minimizing time loss while ensuring cracking resistance
3Productivity
If conventional welding is applied to precipitation-hardened superalloys, then welding speed is maintained, but hot cracking and strain-age cracking occur
Solution Approach 1:
The patent applies preliminary pre-weld overageing treatment to modify the microstructure before welding, growing coarse gamma prime particles that reduce lattice misfit. This preliminary action enables subsequent welding at normal speeds without hot cracking or strain-age cracking, as the pre-modified microstructure is much more crack-resistant
Solution Approach 2:
The pre-weld overageing treatment performs a preliminary anti-action by counteracting the cracking tendency before welding occurs. By growing coarse gamma prime particles in advance, the treatment creates a microstructure that resists the thermal stresses and lattice misfit that would otherwise cause hot cracking and strain-age cracking during welding
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 reduces the risk of cracking and enhances weld quality by minimizing gamma/gamma prime lattice misfit and internal stresses, thus simplifying the process and shortening manufacturing/repairing times.
Implementation Method 1
melting of superalloy material adjacent the weld joint to be produced in one or more sections is performed by directing a power beam towards the section and longitudinally oscillating the power beam within the section
Implementation Method 2
The intensity and frequency of oscillation of the power beam are selected such that the superalloy material adjacent the weld joint to be produced are caused to become uniformly heated and melt, thereby producing the weld joint from the consolidation of the superalloy material so melted
Data Source
AI summary
System and method for welding a precipitation-hardened superalloy, e.g., Nickel-based superalloy, article to produce a weld joint, wherein one or more sections are defined longitudinally within the entire length of the weld joint to be produced, melting of superalloy material adjacent the weld joint to be produced in one of the one or more sections is subsequently performed, by directing a power beam towards the section and longitudinally oscillating the power beam within the section, an intensity of the power beam and a frequency of oscillation of the power beam are selected such that the superalloy material adjacent the weld joint to be produced are caused to become uniformly heated and melt thereby producing the weld joint from the consolidation of the superalloy material so melted, where the weld joint is thereafter solidified by gradually reducing the power beam intensity while oscillating longitudinally the power beam within the section.