It is a question often asked by engineers, supply chain professionals, and shop managers alike. Surprisingly, the answer is more straightforward than one might suspect. While a laser is still a relatively expensive tool to operate, the benefits offered in the re-manufacturing of critical components are substantial, especially under life cycle cost considerations.
What is laser cladding?
Laser cladding is an additive manufacturing process. The technology utilizes a laser to melt and bond metal alloy layers to a worn or damaged component. The typical laser cladding thickness ranges between 0.020″ and 0.060″ per layer. Laser Welding Solutions tailors the specific layer thickness to the exact requirements of the damaged part. In cases where several cladding layers are stacked on top of each other to restore a geometry and create a 3-dimensional shape, the process is also called Laser Metal Deposition.
What parts are being re-manufactured with laser cladding?
Re-manufacturing with laser cladding is rapidly growing in several industries, such as energy, mining & extraction, chemical, and transportation. The list ranges from main shafts, roller shafts, bearing journals, sealing surfaces, valve seats to more complex geometries such as impellers, turbine blades, and die plates.
What are the most important distinguishing characteristics of the laser cladding process for re-manufacturing?
The best-known characteristics of laser cladding and laser metal deposition are the high precision and low heat impact for the repair component. Laser cladding is still a welding process by nature. The laser energy does melt the surface of the base metal to create the desired metallurgical bond with the added alloy. Laser Welding Solutions has prioritized the minimization of this surface melting. As a result, there are typically no undesired heat-related effects of the un-damaged areas of the part requiring re-manufacturing.
In addition, the laser cladding process typically delivers excellent metallurgical characteristics. This important distinguishing aspect tends to be overlooked by many when comparing the laser process to arc-overlaying technologies. The high energy density of the laser rapidly increases the local surface temperature above melting for a short time only. The weld cools faster, resulting in a more fine dispersed grain structure with better mechanical properties. This grain structure further helps to increase the service life of the re-manufactured or re-conditioned component.
What are typical laser cladding metal alloys?
Another reason why laser cladding is increasing rapidly in popularity is the wide range of metal alloys available for rebuilding geometries and protecting surfaces. In re-manufacturing and re-conditioning, the selected materials potentially withstand service wear and tear much better than the original material. Think of seal or bearing surfaces re-manufactured with more corrosion or wear-resistant alloys than the original machined component. Popular laser cladding alloys include nickel-and cobalt-based superalloys such as Inconel 625, Inconel 718, Stellite 6, Stellite 21, or stainless steels such as SS316 or SS17-4. It is also possible to conduct laser re-conditioning with the same or similar alloy as the original material.
What are the differences between powder laser cladding and wire laser cladding?
The laser cladding process produces high-quality protective layers with the metal alloy added in powder or wire form. There are more alloys available in powder form than in wire. The powder is delivered into the laser process either centered around the laser beam (coaxially) or from the leading/trailing sides (off-axially). Laser Welding Solution prefers the coaxial feeding for the re-manufacturing of 3-dimensional geometries, while we use off-axis feeding for large area claddings.
Laser cladding with wire offers greater efficiency, as the wire melts entirely in the melt puddle. In comparison, the powder feeding process only has a feeding efficiency of about 85%. Laser Welding Solutions prefers wire feeding for applications that require cladding in vertical positions. We also use it for the rebuilding of certain specific internal part geometries.
How is quality checked and maintained during laser cladding?
The laser cladding process has several critical input parameters such as base material preparation, powder or wire metal alloys, laser- and machine settings. Our welding engineers and Certified Weld Inspectors prepare a Weld Procedure Specification (WPS) for review by the customer that captures the critical parameters for set-up and laser cladding to ensure a high-quality and repeatable process. The WPS is qualified either per LWS or ASME Section IX standards. In addition, we offer reviews and qualifications by external auditing companies such as Det Norsk Veritas (DNV), American Petroleum Institute (API), and others.
Laser Welding Solution utilizes several in-process control and monitoring systems that ensure the highest-quality laser re-manufacturing process.
Laser cladding and laser metal deposition are two examples of modern manufacturing technologies emerging today as we strive to save natural resources and lower life-cycle costs. The re-manufacturing with laser cladding can save both time and money over purchasing a new original component, even if the damaged part has more complex 3-dimensional geometries. Many companies are selecting laser technology today to re-condition an OEM component and at the same time improve wear- and corrosion-critical characteristics.
Please find more information on our website under “laser cladding“.
Or join our Ed Peterson for his joint presentation at the AWS virtual conference “Corrosion Prevention and Management of Welds“.
Ed and Bill Valerioti with Chevron Phillips Chemical will present the re-manufacturing of a 50+ inch diameter die plate for a chemical application.