The oil and gas industry relies on centrifugal compressors, steam turbine shafts, gas rotors, impellers, rotating blades, and other pieces of large equipment. Not only that, this machinery is often pushed to its operational limits. Erosion, wear and tear, stress, and extensive use take their toll on these components, resulting in worn out parts and breakdowns. Laser cladding is an effective repair technique that rebuilds parts by resurfacing them. Laser cladding improves quality and reduces the scrapping of worn out components.
What is Laser Cladding?
According to a whitepaper published by GE Oil and Gas on laser cladding, laser surfacing can be broken into the following two categories:
- Thermal processes - For example, the melting and hardening of materials that change the microstructure of the surface.
- Thermochemical processes - For example, modifying the surface by adding new materials such as alloying and cladding.
Laser cladding uses laser beams to metallurgically bond coatings to worn components, creating a three dimensional repaired product with the same dimensions as the original. The laser melts a base material into a "melt pool." From there, the coating material is introduced and melted, creating a metallurgical bond.
With laser cladding, a special welding system containing a laser is used to fill a component's flaw. The laser beam melts the additive material and substrate, creating a metallurgical bond. Depending on the component, multiple layers may be needed to reach the desired thickness. Lower melting volumes and higher heating and cooling rates give laser cladding an advantage over traditional welding.
Laser cladding has many uses in the oil and gas industry including:
- Repairing worn parts
- Improving the surface and retention of cutting edges and blades
- Preparing parts for highly abrasive conditions
- Improving wear and tear
Laser cladding also offers many advantages over traditional welding such as improved wear performance, fully fused to metal repairs, and small heat affected zones -- all at a cost-effective price.
Advances in Laser Cladding
Recent advances in laser cladding application include:
- Fiber lasers - These lasers are extremely stable and highly concentrated with a high quality beam. They are also extremely efficient, easy to cool, and easy to use.
- Direct-diode lasers - According to Coherent, its "...next generation direct-diode laser series delivers both high power and an increased range of 'smart' output beam shapes, making it the ideal source for laser heat treating, cladding, and welding applications -- all at faster speeds, greater deposition rates and larger areas. The higher power and longer line beam of these advanced lasers increase production speeds to new benchmark levels and allow larger areas to be processed in a single pass in cladding and heat treating applications. In addition, these lasers yield a higher material deposition rate (up to 20 pounds per hour) allowing the laser to 'paint-on' metal."
Advances in laser cladding make it possible to fabricate new 3D parts as well as repair and resurface worn ones. Cost advantages coupled with production advantages make switching to laser cladding an obvious choice for the oil and gas industry.
1. GE Oil & Gas, "Advanced laser cladding application for oil and gas components," - http://site.ge-energy.com/businesses/ge_oilandgas/en/newsletter/geog_viewsandnews_103012/pdf/GEOG_TI2012_Advanced_laser_cladding_application_for_oil_and_gas_components.pdf
2. Coherent, "HighLight D-Series," - http://www.coherent.com/products/?1993/HighLight-D-Series
3. University of Southampton - Optoelectronics Research Centre, "How Fibre Lasers Work," - http://www.orc.soton.ac.uk/61.html