The present disclosure generally relates to laser cladding and, more specifically, to a hybrid laser cladding system that is capable of both powder feeding and wire feeding.
Laser cladding is a surface treatment technology used in many industries such as construction, agriculture, mining, automotive, marine, power generation, and aerospace industries. As a method of hardfacing, laser cladding may be used to apply a cladding layer that enhances various mechanical and/or chemical properties of a base material, such as the wear, erosion, abrasion, impact, corrosion, and/or oxidation resistance of the base material. In such applications, the base material/substrate surface may be metallic, and the applied cladding layer may include hard particles immersed in a metallic matrix or binder to provide an extremely hard and wear-resistant surface.
In a laser cladding operation, a laser may be projected onto the surface of the substrate, causing a thin layer of the substrate surface to melt and produce a localized “melt pool”. The cladding layer metal matrix/hard particles may be fed into the laser beam and melt pool to cause the cladding layer material to at least partially melt and combine with the melt pool at the substrate surface. Upon resolidification, the cladding layer may be fused to the substrate surface with a strong metallurgical bond.
Currently, the cladding layer material is fed into the melt pool/laser beam in either powder or wire form through a laser cladding nozzle. For example, U.S. Patent Application Number 2006/0065650 discloses a laser cladding nozzle having a hollow central projection for conveying the laser out of the nozzle through an opening, as well as powder channels that feed powdered cladding material out through the opening of the nozzle to the substrate surface. In other nozzle designs, a wire channel may be used instead of a powder channel to feed the cladding material in wire form onto the substrate surface.
The selection of powder or wire feeding is often determined by the material form availability, the material chemistry, the shape and size of the part, among various other considerations. However, powder and wire feeding are both associated with distinct advantages and disadvantages. For instance, wire feeding cannot support more than about 30-35% volumetric fraction of hard particles due to the limiting holding capacity of the wire. In addition, wire feeding is unidirectional, and may result in irregular cladding layer thicknesses due to poor detachment of the wire from the melt pool as may occur, for example, when applying the cladding layer by rastering. In contrast, powder feeding can support a high volumetric fraction of hard particles, and spreads on the substrate surface to provide multidirectional deposition. Moreover, powder feeding does not involve wire detachment and, therefore, may provide a smooth surface with an even thickness. On the other hand, powder feeding may be limited by material form availability, powder material chemistry, as well as the shape and size of the part to be treated.
Thus, a laser cladding nozzle configured for only one of powder or wire feeding may not be optimal for many applications. Accordingly, there is a need for improved laser cladding system designs.
In accordance with one aspect of the present disclosure, a hybrid laser cladding nozzle configured to both powder feed and wire feed a cladding layer onto a substrate surface is disclosed. The hybrid laser cladding nozzle may comprise a central laser channel configured to project a laser beam onto the substrate surface to produce a laser beam spot thereon. The hybrid laser cladding nozzle may further comprise a powder channel coaxial to the laser channel that is configured to feed a powder material onto the laser beam spot, and at least one wire channel laterally disposed with respect to the central laser channel and the powder channel. The wire channel may be configured to feed a wire onto the laser beam spot. The laser beam spot may be configured to melt the powder material and the wire to produce the cladding layer on the substrate surface.
In accordance with another aspect of the present disclosure, a hybrid laser cladding system for depositing a cladding layer onto a surface of a substrate by powder feeding and wire feeding is disclosed. The hybrid laser cladding system may comprise a fixture configured to support the substrate, and a laser cladding head having a laser cladding nozzle that includes nozzle tip with a nozzle opening and a wire opening. The laser cladding nozzle may further include a central laser channel configured to project a laser beam through the nozzle opening onto the surface of the substrate to produce a laser beam spot on the surface. In addition, the laser cladding nozzle may further include a powder channel coaxial to the laser channel that is configured to feed a powder material onto the laser beam spot through the nozzle opening, and at least one wire channel laterally disposed with respect to the laser channel and the powder channel that is configured to feed a wire onto the laser beam spot through the wire opening. The laser beam spot may be configured to melt the powder material and the wire to produce the cladding layer on the surface of the substrate. The hybrid laser cladding system may further comprise a laser power supply configured to produce the laser beam, and a hot wire supply configured to preheat the wire in the wire channel.
In accordance with another aspect of the present disclosure, a wear component having a body with a metallic surface and a cladding layer deposited on the surface is disclosed. The cladding layer may be deposited on the surface of the wear component by a method comprising aligning a laser cladding nozzle with the surface, wherein the laser cladding nozzle includes a laser channel, a powder channel coaxial to the laser channel, and at least one wire channel laterally disposed with respect to the laser channel and the powder channel. The method may further comprise projecting a laser beam through the laser channel onto the surface of the component to produce a laser beam spot, and the laser beam spot may at least partially melt the surface to produce a melt pool at the laser beam spot. In addition, the method may further comprise feeding a wire through the wire channel onto the laser beam spot to melt the wire into the melt pool, and feeding a powder material through the powder channel onto the laser beam spot to melt the powder material into the melt pool. The wire may include a metal matrix, and the powder material may include hard particles. The method may further comprise allowing the melt pool to resolidify at the surface of the component to provide the cladding layer.
These and other aspects and features of the present disclosure will be more readily understood when read in conjunction with the accompanying drawings.
Referring now to the drawings, and with specific reference to
The material construction of the wear component 12 is depicted in
Turning to
The system 29 may further include a fixture 34 for supporting the substrate 24, a powder feeder 40 for supplying powder material to the nozzle 32 via one or more supply conduits 42, as well as one or more wire feeders 44 for feeding the wire(s) 38 to the nozzle 32. Connected to the cladding head 30 may also be a laser power supply 46 which serves as an energy source for producing the laser beam 36. Furthermore, the system 29 may also include a hot wire power supply 48 in connection with the cladding head 30 to preheat the wire(s) 38, such as by resistive heating, to a temperature below its melting point prior to deposition on the substrate surface 26. Preheating of the wire(s) 38 in this way may reduce the energy input required by the laser beam 36 to melt the wire(s) 38.
Optionally, a controller 50 may be in electrical communication with one or more of the wire feeder(s) 44, the powder feeder 40, the laser cladding head 30 (and the nozzle 32), the laser power supply 46, the hot wire power supply 48, and the fixture 34 for automated control thereof. Namely, the controller 50 may control numerous parameters of the laser cladding operation such as the laser power via the laser power supply 46, the preheated temperature of the wire(s) 38 via the hot wire power supply 48, the rate of powder and wire feeding through the powder feeder 40 and the wire feeder(s) 44, respectively, as well as the movement of the fixture 34/substrate 24 relative to the nozzle 32. Moreover, the controller 50 may control whether the system 29 deposits the cladding layer 23 by powder feeding, wire feeding, or by a combination of powder and wire feeding by activating and deactivating the powder feeder 40 and the wire feeder(s) 44 accordingly. In alternative arrangements, the laser cladding system 29 may be manually controlled. For example, the system 29 may include one or more user-actuatable switches 52 that permits a user to select between powder feeding, wire feeding, and a combination of powder feeding and wire feeding. Likewise, the system 29 may also include various other switches/controls that enable a user to select the laser power, the feed rates of the powder feeder 40 and the wire feeder(s) 44, and the movement of the head 30/nozzle 32 with respect to the fixture 34/substrate 24.
In operation of the laser cladding system 29, the laser beam 36 may be projected onto the substrate surface 26 through the nozzle 32 to produce a laser beam spot 54 on the surface 26. The laser beam spot 54 may at least partially melt a thin layer of the surface 26, producing a melt pool 56. As the laser beam 36 is projected onto the surface 26, the cladding layer material (as a powder material and/or as one or more wires 38) may be fed into the laser beam spot 54 and the melt pool 56 through the nozzle 32, allowing the cladding layer material to at least partially melt and combine with the melt pool 56. Upon resolidification, the cladding layer 23 may be fused with the surface 26 of the substrate 24 with a strong metallurgical bond therebetween. The fixture 34/substrate 24 and the nozzle 32 may be moved with respect to each other to cover the desired area of the surface 26 with the cladding material and/or to build up the thickness of the cladding layer 23. In some arrangements, the fixture 34/substrate 24 may be moved relative to the nozzle 32 with the nozzle 32 held stationary. In other arrangements, the nozzle 32 may be moved relative to the fixture 34/substrate 24 while the fixture 34 and the substrate 24 are held stationary.
The hybrid laser cladding nozzle 32 is shown in cross-section in
Laterally disposed with respect to the laser channel 58 and the powder channel 65 may be a wire channel 70 that feeds one or more wires 38 into the laser beam 36 and the melt pool 56. The wire 38 may exit the wire channel 70 and the nozzle 32 through a wire opening 72 at the tip 62 that is separate from the nozzle opening 60. To allow multidirectional wire feeding, the nozzle 32 may optionally include a plurality of wire channels 70 laterally distributed around the laser channel 58 and the powder channel 65, and each of the wire channels 70 may be configured to feed its respective wire(s) 38 through a separate wire opening 72 surrounding the nozzle opening 60 (see
In other alternative arrangements, the nozzle 32 may include a laterally disposed powder channel 65 in addition to or in place of the coaxial powder channel, as shown in
As will be understood by those with ordinary skill in the art, the nozzle 32 may also include additional features such as one or more cooling channels for cooling the nozzle 32, and/or one or more shielding gas channels for shielding the laser beam 36 and the powder and/or wire cladding material with an inert gas as it is projected to the substrate surface.
The hybrid laser cladding nozzle 32 disclosed herein offers many advantages over laser cladding nozzles of the prior art that are limited to either powder feeding or wire feeding. By combining powder feeding and wire feeding, the laser cladding nozzle 32 disclosed herein offers the opportunity to blend cladding materials available in powder and wire form. For instance, as wire feeding alone has a low capacity for hard particles, a cladding layer 23 with a high hard particle content (more than about 35% by volume) may be produced by co-depositing or subsequently depositing hard particles in powder form. Moreover, powder feeding may be leveraged during or after wire deposition to smoothen out and improve the thickness uniformity of an uneven surface caused by poor wire detachment from the melt pool. Powder feeding may also be leveraged to provide multidirectional deposition of the cladding materials that cannot be realized with single wire feeding alone. Multidirectional deposition may also be realized by feeding the wires 38 onto the surface through multiple wire channels 70 laterally distributed around the laser channel 58, as described above.
Turning now to
In general, the teachings of the present disclosure may find applicability in many industries including, but not limited to, industries using components with cladding layers. More specifically, the teachings of the present disclosure may be applicable to any industry relying on laser cladding to produce wear-resistant cladding layers on wear components.
The hybrid laser cladding system disclosed herein permits deposition of cladding layers via either or both of powder feeding and wire feeding. Simultaneous powder feeding and wire feeding may allow for higher deposition rates than can be achieved with just powder or wire feeding alone. In addition, as disclosed herein, the hybrid laser cladding system may be used to deposit cladding layers with hard particle contents well above the holding capacity of wire (about 35% by volume) by allowing the simultaneous or subsequent deposition of hard particles in powder form. Thus, the wear-resistance and/or abrasive properties of the resulting cladding layers may be significantly improved over cladding layers fabricated by wire feeding alone. Alternatively or in combination with this, compositional gradients in the cladding layer may be produced with the hybrid nozzle by gradually increasing the feeding rate of the powder or wire material. Moreover, multidirectional deposition may be achieved by either or both of powder feeding and wire feeding though multiple wire channels distributed around the nozzle. The hybrid nozzle also allows rough and uneven surfaces caused by wire feeding to be corrected with simultaneous or subsequent powder feeding. Further, components having distinct core and surface composition may be fabricated using by first building the core of the component by wire feeding, and then depositing an outer layer of distinct composition by powder feeding. Many possibilities such as these may be envisioned. It is expected that the technology disclosed herein may find wide industrial applicability in a wide range of areas such as, but not limited to, additive manufacturing, road construction, construction, agriculture, mining, automotive, marine, power generation, and aerospace applications.