Laser Cladding and Thermal Spray are two distinct techniques used to enhance surface properties in various industrial applications. Both technologies are effective for hard-facing, corrosion resistance, and dimensional restoration, but they each offer unique advantages. This blog delves into the strengths and ideal uses of Laser Cladding and Thermal Spray processes.
What is Laser Cladding?
Laser Cladding is an advanced overlay process designed to improve the surface properties of metals. In this technique, a laser melts a filler material—either in wire or powder form—and bonds it to the substrate. This creates a metallurgical bond that results in a coating with minimal distortion and less than 1% dilution with the substrate.
Figure 1: Laser Cladding Repair on 15ft Long Shaft at Synergy Additive Manufacturing
What is Thermal Spray?
Thermal Spray involves using gas or electricity to generate a flame that melts a wire or powder material, which is then sprayed onto the substrate at high velocities. This process creates a mechanical bond, where the coating adheres through physical attachment or interlocking with the substrate.
Figure 2: Thermal Spraying. (2024, August 5). In Wikipedia.
When Laser Cladding Shines
Laser Cladding excels in applications where a robust metallurgical bond is essential. This process is particularly effective for parts subjected to torsional and fatigue loading, such as shafts, bearings, and sealing surfaces. It is also ideal for applications requiring efficient heat transfer from the coating to the substrate, such as boiler tubes in thermal power plants. In applications requiring high-wear for components in the oil and gas industry, mining excavators, and automotive parts and in applications where where near-zero porosity and defect-free coatings are critical, Laser Cladding emerges are a real winner.
When Thermal Spray Shines
Thermal Spray is advantageous in scenarios where no melt pool is created, allowing for the application of high-hardness coatings, like Tungsten Carbide, without risking cracks in the coating. This is beneficial for valves and sealing applications that demand high hardness. Thermal Spray is well-suited for depositing very thin metal layers (less than 0.010”), making it ideal for applying Thermal Barrier Coatings (TBC).
Figure 3: Comparison Between Laser Cladding and Thermal Spray
Cost Comparison: Laser Cladding vs. Thermal Spray
The cost of each process can vary significantly based on the application, material selection, and part size. However, with advancements in high-power laser technology, the cost of laser cladding per square inch—considering material preparation, buildup, and post-machining—is becoming competitive with that of thermal spray coatings.
Summary
Both Laser Cladding and Thermal Spray are valuable technologies in manufacturing, each with its own set of advantages. Laser Cladding offers precise control over material thickness and creates a strong, homogeneous metallurgical bond with near 100% dense coatings, reducing the risk of chipping and delamination of the coating. In contrast, Thermal Spray is ideal for applications requiring crack free high hardness coatings such as Tungsten Carbide and applications that require very thin metal layers. Understanding the specific requirements of your application will help determine which process is best suited to meet your needs.
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