Spray Welding & Cold Spray Guide: Your Complete Overview
The Spray Welding Guide explores how this versatile process can repair, restore, or improve metallic surfaces. It combines speed, precision, and cost-effectiveness, making it a go-to solution for industries like aerospace, automotive, manufacturing, defence, and tooling.
In this guide, you’ll learn what spray welding is, its variations, advantages, and why it stands out compared to traditional welding methods like MIG or arc welding. Let’s dive in!
What is Spray Welding?
Spray welding is a thermal process where molten or semi-molten material is sprayed onto a surface to coat or repair components. Unlike traditional welding, it doesn’t require melting the substrate entirely. This feature makes spray welding ideal for delicate or complex structures.
Common energy sources for spray welding include:
- Flame-sprayed systems, which use combustible gas to melt the material.
- Plasma spray systems, relying on ionised gas for high-energy coatings.
- Cold spray systems, using supersonic gas jets to bond particles without significant heat.
Read more about Cold Spray and Spray Welding from Science Direct.
What is Cold Spray?
Cold spray is an advanced coating and repair technology that operates at significantly lower temperatures compared to traditional spray welding methods. Instead of using heat to melt the material, cold spray relies on supersonic gas jets to accelerate fine metal or alloy particles onto a substrate. These particles bond upon impact through plastic deformation, without melting.
Key Differences Between Cold Spray and Spray Welding:
- Temperature:
- Spray welding involves high heat to melt the coating material.
- Cold spray uses minimal heat, ensuring no thermal distortion or substrate damage.
- Material Bonding:
- Spray welding relies on molten particles adhering to the substrate.
- Cold spray creates a mechanical bond through high-velocity particle impact.
- Applications:
- Spray welding is better for high-temperature coatings and repairs.
- Cold spray excels in repairing temperature-sensitive materials and creating lightweight structures.
- Surface Integrity:
- Spray welding risks altering the base material’s properties due to heat.
- Cold spray maintains the substrate’s original properties, making it ideal for critical applications.
Why Choose Cold Spray?
Cold spray offers unique advantages that make it stand out:
- Preserves Base Material Integrity: Minimal heat ensures no thermal degradation.
- High-Performance Coatings: Produces dense, durable coatings resistant to corrosion and wear.
- Wide Material Compatibility: Works with temperature-sensitive materials like aluminium, magnesium, and composites.
- Rapid Repairs: Reduces downtime by enabling quick, in-situ restoration of parts.
Advantages of Spray Welding
Here are some key advantages of spray welding:
- Reduced Heat Distortion: It preserves the substrate’s integrity.
- Versatility: Suitable for metals like aluminium, cast iron, and high-performance alloys.
- Precision: Ideal for surfaces needing even coatings or accurate repairs.
- Cost-Effectiveness: Less material waste and faster repairs save costs.
Spray Welding Variations
Spray welding offers multiple variations for different applications:
- Thermal Spray Welding: Includes flame and plasma spraying, providing durable coatings and corrosion resistance.
- Cold Spray Process: Uses high-velocity particles to bond without melting, perfect for temperature-sensitive materials.
- Spray Weld Repair: Restores worn components like shafts or cast iron parts without complete replacement.
Applications of Spray Welding
Spray welding is widely used in industries such as:
- Aerospace: Repairing turbine blades and adding heat-resistant coatings.
- Automotive: Rebuilding engine components and protecting against wear.
- Manufacturing: Coating and restoring expensive machinery parts.
- Oil and Gas: Repairing corroded pipelines and applying protective coatings.
Future of Spray Welding
Spray welding continues to evolve with technological advancements. For instance, robotics and AI-driven process optimisation improve precision and efficiency. Cold spray technology is also unlocking new possibilities for lightweight structures and advanced coatings. Industries like aerospace and defence will greatly benefit from these innovations.
Conclusion
Spray welding is a game-changing technology for modern industries. It offers unmatched precision, durability, and cost-efficiency for repairing, restoring, and improving metallic components. Cold spray, as an innovative subset of this technology, adds further value by enabling advanced coatings and repairs without thermal distortion. This guide has shown how spray welding and cold spray meet today’s industrial challenges, making them essential tools for manufacturing and beyond.
To learn more about cold spray and its comparison to other spray welding methods, read more here:
How does cold spray work?
Advantages of Cold Spray Additive Manufacturing
Industry-leading speed
Build high-performance metal parts at 5-6kg per hour, competing directly with commercial, traditional manufacturing methods.
Minimal size constraints
Cold spray can build very large metal parts with minimal limitations, with systems designed for parts 3-9 metres in length or larger.
Near-net shape manufacturing
Build parts to near their final desired shape, saving up to 90% of machining waste and saving time and costs.
Multi-metal, seamless parts
Build single-piece parts seamlessly with multiple metals, from titanium, steel, copper, and much more.
Why Cold Spray Additive Manufacturing?
Cold spray additive manufacturing stands out the most in industries where durability and precision are essential:
Heat-Free Application
Cold spraying doesn’t melt materials, significantly reducing thermal stress and preventing undesirable changes in the material’s microstructure. This preserves the material’s original strength, toughness, and resistance to corrosion.
Enhanced Mechanical Properties
Parts made through cold spray usually have mechanical properties superior to those made with traditional methods, including higher density and improved tensile strength. Unlike traditional methods, cold spray avoids thermal cycling, preserving the material’s structural integrity.
Read more about Titomic’s material capabilities here.
Tailor the Manufacturing Process, Tailor the Part
By manipulating the variables of cold spray, such as metal, gas pressure, and temperature, certain mechanical properties can be achieved based on the part requirements, such as ductility, hardness, and so on. Importantly, these characteristics can be altered within the same part.
For example, a steel ballistics plate could feature a very hard strike face, while the rear portion of the plate could be made more ductile, while also featuring titanium for weight reduction.
Fusion of Dissimilar Metals
Because the process doesn’t melt metals, those with different melting points can be fused together. This allows for leveraging the strengths of multiple metals within a single, seamless part, without joining or welding.
For instance, ballistics panels can combine steel and titanium, or aluminium can be applied to steel to remove and protect against corrosion.
Rapid Deposition and Scalability
Cold spray is a fast and scalable additive manufacturing process. It can be used to build large structures quickly, making it highly adaptable across various applications. For example, large pure titanium parts can be built at speeds of 5–6 kilograms per hour.
Large Scale
Cold spray doesn’t require an inert environment, unlike many melt-based methods. This allows for the production of large-scale parts without size limitations.
Minimal Waste
Because the powder particles are directly deposited onto the surface, there is minimal material waste, making cold spray technology environmentally and economically advantageous.
Compatibility with Diverse Materials
You can use cold spray with a wide range of materials, including:
- Commercially pure titanium and Ti-6Al-4V
- Steel and steel alloys
- Inconel 625 and 718
- Aluminium alloys including 6061 and 7075
- Silver, gold, and other precious metals
- Tantalum and other refractive metals
- Tungsten alloys
- Magnesium alloys
- Invar36
- Certain ceramics
Frequently asked questions
TKF costs significantly less than traditional manufacturing methods for the following reasons:
- It doesn’t need large-scale tooling (such as vacuum moulds) to produce parts. A simpler setup means reduced costs.
- It turns metal powder to part in just hours, by depositing the powder at supersonic speed to rapidly build up parts layer by layer – so there’s no need for casting or forging. Plus, the part you need is the part you make, saving time and materials.
- It keeps material costs down. For example, when we manufactured a 1.2m titanium ring, the ‘as built’ weight was 60kg while the final part weighed 56kg – representing a ‘buy to fly’ ratio of 1.08 with material costs of only A$3,000.
Our compact cold spray systems cost considerably less than traditional repair and resurfacing methods for the following reasons:
- You can resurface and refurbish parts in just minutes.
- Materials often cost less than $300.
- You no longer need to outsource repairs. For example, a shower floor manufacturer quoted $40,000 to ship a damaged resin transfer moulding tool overseas spent just $3,000 repairing it with Titomic’s D523 system – as well as saving months of downtime.
We’ve achieved typical density rates of 90-95% and over 99% when enhanced by post-processing.
If needed, it’s also possible to create less dense, more porous coatings for grip, abrasion, chemical processing and more through process optimisation, powder manipulation, and post-processing parameters.
Generally, you can achieve mechanical properties similar to casting and forging. While some parts may need to be processed with a heat treatment to make them more ductile, we can tailor process variables to meet your specific needs – a clear advantage compared to other methods.
It depends on what parts you need, as well as the mechanical properties the application requires. However, generally parts created with TKF will need some post-processing heat treatment.
Cold spray doesn’t require heat to melt the materials being sprayed. This is different to traditional metal spraying methods like welding or thermal spraying, which use heat to melt the material before it’s applied to a surface.
Instead, a high-pressure gas is used to accelerate tiny metal particles (which are usually less than 50 micrometres in size) to supersonic speeds. This creates heat through kinetic energy, when the particles collide with the surface of the object being sprayed.
Cold spray works by exploiting the kinetic energy of tiny metal particles. Low-to-high pressure gas is used to accelerate the particles (which are usually less than 50 micrometres in size) to supersonic speeds. These are then sprayed onto a surface where they compress and deform to create a cohesive bond.
This results in a strong, dense coating that can be used for a variety of applications – such as repairing damaged parts, improving the surface properties of a material, or creating new, complex shapes.
There are many metals that can be used in our cold spray systems. This includes aluminium, copper, nickel, titanium, stainless steel, Inconel, and more.
Since these all have different characteristics – such as strength, ductility, and resistance to corrosion – the chosen metals will depend on the application, as well as the properties needed for the final product.
Some metals may also be easier or more difficult to cold spray, depending on their melting point, ductility, and other factors.
What makes TKF so beneficial is that it can fuse dissimilar metals together. This means you can leverage the strengths of multiple metals in a single, monocoque part. For instance, you can fuse copper to titanium, nickel to cast iron, and much more.
Cold spray can be used on a variety of surfaces. This includes metals, ceramics, plastics, and composites.
The process is particularly useful for repairing worn or damaged metal parts, as it can restore the surface to its original shape and properties without causing distortion or weakening the material.
Our cold spray systems can also be used to add new features or properties to a surface, such as improved wear resistance, corrosion resistance, or thermal properties.
You can even use it to create new shapes or structures that would be difficult or impossible to achieve with traditional manufacturing methods.
- Aerospace: Repair and restore worn or damaged aircraft parts (such as engine blades, landing gear, and wing components), or add corrosion-resistant coatings to aircraft surfaces.
- Automotive: Repair and restore worn or damaged engine components (such as pistons, cylinder heads, and crankshafts), or add wear-resistant coatings to automotive parts.
- Marine: Repair and restore worn or damaged marine components (such as propellers, shafts, and rudders) or add corrosion-resistant coatings to marine structures.
- Oil & gas: Repair and restore corrosion and wear (such as shafts, bearings, piping, and valves).
- Electronics: Add conductive coatings to electronic components (such as circuit boards and antennas), as well as repair and restore electronic devices.
- Manufacturing: Create new shapes or features on metal parts (such as textured surfaces or complex geometries), or add wear-resistant coatings to industrial components (such as machine tools and moulds).
