Metallic Artifact Repair via Cold Forging and Laser Cladding
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Solution Overview
Problem
Conventional arc welding is unsuitable for repairing metallic artefacts with wet surfaces due to arc instability and porosity issues, making it difficult to seal leaking cracks in vessels without draining or venting, which is costly and disruptive in industrial settings.
Innovation Solution
A method combining cold forging to close defects and laser cladding with overlapping beads to form a cladded metal layer, allowing in-situ repair of metallic artefacts, including vessels under pressure, without electrical contact and shielding, using hammer peening and laser cladding with controlled process parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If arc welding is used to repair metallic artefacts, then welding strength is improved, but arc stability deteriorates due to moisture on the surface
Solution Approach 1:
The patent replaces the arc welding process with a cold forging process that uses mechanical impact (hammer peening) to close defects. This substitution eliminates the need for electrical arcs entirely, allowing repair of wet metallic surfaces where arc stability would be compromised by moisture
Solution Approach 2:
The patent changes the fundamental parameters of the repair process by transitioning from a thermal process (arc welding) to a mechanical process (cold forging). This parameter change allows the repair to proceed on wet surfaces without the arc stability issues that plague conventional welding
2Reliability
If arc welding is used to seal leaking cracks, then sealing effectiveness is improved, but porosity increases due to moisture
Solution Approach 1:
The patent replaces arc welding with laser cladding, substituting a thermal arc process with a controlled laser-based deposition process. This eliminates the porosity caused by moisture interaction with the arc, while the laser's precise energy delivery ensures high-quality, pore-free cladded metal
Solution Approach 2:
The patent extracts and removes the harmful effect of moisture from the repair process by using cold forging to close defects before laser cladding. This sequential approach separates the moisture-closing function from the sealing function, preventing moisture-induced porosity in the final repair
3Ease of manufacture
If the vessel is drained or vented for repair, then repair accessibility is improved, but production downtime increases
Solution Approach 1:
The patent enables the vessel to remain in service during repair by using in-situ cold forging and laser cladding techniques. The process works on pressurized, wet surfaces without requiring the vessel to be drained or vented, allowing continuous operation and eliminating production downtime
Solution Approach 2:
The patent performs preliminary cold forging to close defects before applying the laser cladding layer. This preliminary action prepares the surface in-situ without requiring vessel shutdown, enabling subsequent sealing operations while the vessel remains pressurized and in service
4Reliability
If cold forging is used to close defects, then defect closure is achieved, but surface distortion may occur
Solution Approach 1:
The patent applies cold forging locally to close defects while the laser cladding process subsequently restores and refines the surface quality. The local mechanical action closes the defect, and the localized thermal processing of laser cladding reheats and smooths the affected area, eliminating surface distortion
Solution Approach 2:
The patent creates a composite repair structure where the cold-forged metal and laser-cladded metal form a unified repair zone. The laser cladding layer bonds to the cold-forged surface, creating a composite structure that maintains both defect closure and surface integrity
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
Enables effective sealing of cracks and pores in metallic vessels under pressure without downtime, reducing leakage and avoiding electro-chemical effects, suitable for wet environments and windy conditions, thus minimizing production losses.
Implementation Method 1
laser cladding the cold forged defect with a plurality of laser clad beads applied to the metallic surface or substrate
Implementation Method 2
cold forging the open defect to close the open defect
Implementation Method 3
hammer peening of the open defect
Data Source
AI summary
A method of repairing a metallic artefact (40) with an open defect in or on a metallic surface or substrate of the metallic artefact includes cold forging the open defect to close the open defect and thereafter laser cladding the cold forged defect with a plurality of laser clad beads (44) applied to the metallic surface or substrate to cover the cold forged defect with a cladded metal layer. Advantageously, in-situ repair of fluid-filled vessels, pipes or the like is made possible by the repair method, in some instances eliminates the need to shut equipment down thereby reducing downtime and the cost associated with lost production.