Views: 0 Author: Site Editor Publish Time: 2025-09-13 Origin: Site
Laser cladding and supersonic spraying (mainly HVOF/HVAF) are both advanced remanufacturing technologies, but they are fundamentally different in principle, performance and application scenarios. This paper explains why laser cladding is usually the preferred solution in roller repair.
To get a better idea, we can summarize the differences in the following table:
Dimension of characteristics | Laser cladding (LCL) | Supersonic Spray (HVOF/HVAF) |
Principle and essence | Metallurgical bonding: the high energy laser beam is used to form a molten pool on the surface of the base, and the alloy powder is sent in at the same time, so that it is melted and solidified together with the base material to form a completely metallurgical bonding coating. | Mechanical bonding: The powder is accelerated and heated to semi-melt or full melt state in the high temperature and high speed flame flow, and then collides with the surface of the substrate at high speed. Through violent plastic deformation, the powder is flattened and mechanically anchored on the roughened substrate. |
anchoring strength | Very high (up to the strength level of the matrix material itself). | Higher (but mechanical bonding, usually <100 MPa). |
dilution | Controllable (usually can be controlled below 5%), can maintain the original performance of the coating material. | Almost zero, the coating composition does not mix with the matrix. |
heat input | Centralized, controllable, small heat affected zone, small overall thermal deformation. | Lower but scattered, the base temperature rise is lower, but the heat will accumulate when sprayed over a large area. |
Coating density | Dense, pore-free, metallurgical cast structure. | Very dense (> 99%), but still layered structure, with possible small amounts of oxide inclusions. |
coating layer thickness | The single path can reach 0.5-3mm, which can be easily stacked to repair heavy wear and tear. | It is usually thin (0.1-0.5mm), and thick coatings are prone to large stresses that lead to spalling. |
Matrix requirements | Need to be clean, but not too rough. | Strict sandblasting roughening must be carried out to obtain good mechanical bonding. |
Although laser cladding is the first choice, supersonic spraying is not entirely useless, it is suitable for some very specific scenarios:
Thin coating requirements: HVOF is an excellent choice when only very thin (<0.5mm) wear or corrosion resistant coatings are required.
Low temperature process: For thin wall or small roll that does not allow any thermal effect or deformation of the matrix, the low temperature characteristics of HVOF (the matrix can be controlled below 150°C) are its greatest advantage.
Material sensitivity: When the repair material is extremely sensitive to heat input (such as some aluminum alloys) or ultra-hard tungsten carbide materials, HVOF can avoid the crack problem caused by the possible cladding (but laser cladding process is also improving, and can be well handled for tungsten carbide materials).
On-site disassembly repair: For rollers that cannot be removed from large equipment, portable supersonic spraying equipment may have more operational advantages than mobile laser cladding equipment.
characteristic | laser melting coating | Supersonic spraying |
structure | metallurgical bonding | mechanical joint |
Repair thickness | Thick, medium and thin are all acceptable | Thin-layer only |
Impact/fatigue resistance | rattling | range |
Thermal deformation control | controlled | Low temperature of matrix, but high stress |
applicable scene | Heavy load, heavy restoration, key rollers | Thin coating, low temperature requirement, specific material |
Conclusion: For most roller-type repairs involving harsh working conditions (heavy loads, impacts, fatigue), large repair volumes, and stringent safety and durability requirements, laser cladding emerges as the preferred technology. This is due to its unparalleled metallurgical bonding characteristics, high bonding strength, exceptional impact and fatigue resistance, and capability for heavy-duty repairs. Supersonic spraying serves as a complementary solution, particularly suitable for thin coatings and low-temperature processing requirements.
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