Laser Cladding Also known as laser surfacing, the use of high-energy laser as a heat source, metal alloy powder as a welding material, through the laser and alloy powder on the metal surface of the rapid fusion to form a dense, uniform and the thickness of the metallurgical combination of alloy layer. The material and hardness of the laser cladding layer can be flexibly adjusted as needed. The cladding material: iron, nickel and cobalt.
Laser cladding, also known as laser remanufacturing, or laser repair, is a new surface modification technology.
By adding cladding material to the substrate’s surface, and using a high-energy-density laser beam to melt with the thin layer on the surface of the substrate. The coating forms a cladding layer. The treatment can significantly increase the hardness and wear resistance of the surface and extend the parts’ service life.
Laser Cladding is a weld build-up process and a complementing coating technology to thermal spray. It is increasingly used instead of PTA (Plasma Transferred Arc) welding and easily outperforms conventional welding methods like TIG (Tungsten Inert Gas) for advanced weld repair applications. Due to its superior focusing ability, lasers allow power densities that are not typically possible with conventional thermal procedures. This enables to process components with minimal thermal loading and distortion. Laser cladding is particularly suitable for applications demanding a high dimensional accuracy. Additional applications include materials that are difficult to weld using conventional methods, such as high temperature-resistant nickel-based alloys in gas turbines or tungsten-carbide-filled wear-protection coatings. Typical components include turbine blades, drilling equipment, and pump components.
Lasermach Laser Cladding Process
In laser cladding, the laser beam is defocused on the workpiece with a selected spot size. The powder coating material is carried by an inert gas through a powder nozzle into the melt pool. The laser optics and powder nozzle are moved across the workpiece surface to deposit single tracks, complete layers or even high-volume build-ups.
- Perfect metallurgically bonded and fully dense coatings
- Minimal heat affected zone and low dilution between the substrate and filler material resulting in functional coatings that perform at reduced thickness, so fewer layers are applied
- Fine, homogeneous microstructure resulting from the rapid solidification rate that promotes wear resistance of carbide coatings
- Edge geometries can be coated and built up with welded deposits
- Near net-shape weld build-up requires little finishing effort
- Extended weldability of sensitive matierals like carbon-rich steels or nickel-based superalloys that are difficult or even impossible to weld using conventional welding processes
- Post-weld heat treatment is often eliminated as the small heat affected zone minimizes component stress
- Excellent process stability and reproducibility because it is numerical controlled welding process
The materials applied to laser cladding are relatively wide. It has been successfully developed in stainless steel, dies steel, malleable cast iron, gray cast iron, copper alloys, titanium alloys, aluminum alloys, and special surfaces. And laser clading can be used in a wide range of applications, such as: laser cladding of cobalt-based, nickel-based, iron-based, and other self-fusing alloy powders and ceramic phases.
- Laser cladding of iron-based alloy powders is suitable for parts that require local abrasion resistance and are prone to deformation.
- Nickel-based alloy powders are suitable for components requiring local wear resistance, heat resistance, corrosion resistance, and thermal fatigue resistance.
- Cobalt-based alloy powder is suitable for parts requiring local wear resistance, heat resistance, corrosion resistance, and thermal fatigue resistance.
- Ceramic coating has high strength, excellent thermal stability, and high chemical stability under high temperature, which is suitable for parts requiring wear resistance, corrosion resistance, and high temperature resistance. And oxidation resistance of the parts.
Cemented carbide coating technology is a new surface modification technology that emerged with the development of high-power lasers in the 1970s. It refers to the laser surface cladding technology which combines alloy powder or ceramic powder with a laser beam. The surface of the substrate is rapidly heated and melted. After the light beam is removed, the self-excited cooling forms a very low dilution rate. The surface coating is metallurgically combined with the substrate material, thereby significantly improving the wear resistance, corrosion resistance, heat resistance, oxidation resistance and electrical characteristics of the substrate surface. And other surface strengthening methods.
Laser cladding technology has been applied in various fields. Demand is large, including aerospace, rail transportation, metallurgical and petrochemical, engineering machinery, etc. On various kinds of wearing parts such as drilling tools, picks, rolls, ball valves, valve seats and valve stems, after many traditional surface treatment techniques, hard materials are easy to peel off and have a short service life. Laser cladding additive manufacturing technology is now used to completely avoid such problems. Laser cladding technology has been applied to various materials. Laser cladding strengthens the surface of aluminum alloy to increase hardness and wear resistance, opening up the application of aluminum alloy as a moving part of friction pair. Laser cladding technology replaces the hard chromium plating process, which solves the problems of weak bonding strength, easy peeling, and environmental protection of the latter coating and substrate.
Commonly used cemented carbide coating materials: iron-based cemented carbide, cobalt-based wear-resistant alloy, nickel-based superalloy, nickel-based superalloy plus WC ceramic particulate material as reinforcement, and cobalt-based alloy plus WC ceramic particulate material as reinforcement.
The principle is an accelerated application of the coating on the substrate.
This is done by clamping the workpieces on a lathe.
The laser cladding process is a method of applying a fully dense, metallurgically bonded and virtually pure coating which can be used to increase the wear resistance, corrosion resistance or impact performance of metallic components.
In some cases, all three of the properties can be improved. The process utilises a precisely focused high power laser beam to create a weld pool into which a metallic powder is applied.
The powder, which is carried by a stream of inert shielding gas, is blown co-axially through the laser beam. The highly accurate nature of the laser beam allows fully dense cladding with minimal dilution (<5%), yet with a perfect metallurgical bond.
The Metallisation laser cladding system offers control and integration of the entire cladding process. The system offers control of the process gases, cooling system, laser, powder feed and automation interface safely via an intuitive, touch-screen interface.
The production and processing of steel subjects mill components to combinations of enormous load, high temperature, corrosion, and abrasion. This has the potential to cause many problems throughout the processing line. Modern steel mills have recognized the importance of working with coated rollers. Thermal sprayed components are designed to permit steel to be processed more rapidly and efficiently.
Typical Laser clad components in the steel industry:
- Hot Mill
- Runout table Rolls
- Looper Rolls
- Wrapper Rolls
- Stabilization rods
- Roller bearing seats
- Roller seal rings
- Seal seats
- Rolling Bearing Chocks
- Wear plate surface seats
- Cold Mill
- Bridle Rolls
- Deflector Rolls
- Tensiometer Rolls
- Finishing Lines
- Deflector Rolls
- Flattening Rolls
- Tower Rolls
- Accumulator Rolls
- Pinch Rolls
- Furnace Rolls
- Leveler Rolls
- Downcoiler Rolls
- Pick-up rolls
- Furnace Rolls
- Pickling bath rolls