Engineered Surfaces for Exceptional Performance
Engineered Surfaces for Exceptional Performance

FAQs | MSSA

What is Metal Spray / Thermal Spray?

 

Metal Spraying is a process that has been used for over 100 years around the world, where molten metal or softened particles are applied to a prepared surface (substrate) to enhance its properties (hardness, anti-corrosion, wear, dielectric, restoring dimensions etc.).  No solvents or chemicals are used, just pure metal. Substrate materials include Metals, Glass, Carbon Fibre, Plastics, Plaster, Polystyrene, Ceramics and Wood. Often used as an alternative to the galvanising process, Arc Metal Spraying has low heat input during spraying which eliminates the risk of component distortion. There is no limit to the size of component to be coated with the Metal Spray process and these components can be treated on site, meaning there are no transport or waiting issues. Particular jobs require extra protection in critical areas, the Metal Spray process enables the operator to vary the coating thickness to fulfil that need. 

Our Metal Spray equipment consists of Arc Spray, Flame Spray, Plasma Spray, High Velocity Air-Fuel (HVAF), High Velocity Oxygen-Fuel (HVOF), Laser Cladding, Spray Weld Equipment and also Ancillary Equipment. More information on each process is available by clicking on the relevant tabs.

The process is predominantly used for anti-corrosion, surface modification/enhancement and rebuilding engineering dimensions and has been used in every conceivable industry including Aerospace, Automotive, Marine, Biomedical, Agriculture, Space Travel, Power Generation, Infrastructure, Mining and many more applications. Surface Enhancement applications include, but are not limited to: hard chrome replacement, hard-facing, anti-spark, non-stick, and non-slip coatings.

How Does Metal Spray Compare with Galvanising?

  • A common misconception regarding anti-corrosive coatings is that they can only be completed with Zinc, when in fact Metal Spray can offer 4 variations of anti-corrosion coatings, all of which have their own identities:  Zinc 99.99%, Zinc Aluminium 85/15 alloy, Aluminium 99.5%, and Aluminium Magnesium 5%.
  • No cure time meaning components and structures are ready for use immediately after application.
  • Low heat input during spraying eliminates the risk of component distortion.
  • Low heat input eliminates the risk of thermal metallurgical degradation.

     

    The above video will help to emphasise this low heat input by showing examples
    that would lose definition, distort, warp or even melt when subjected to a high temperature.

  • Sealed hollow fabrications may be treated without risk of explosion.
  • There is no limit to the size of component to be treated.
  • Components can be treated on site, meaning there are no transport or waiting issues.
  • There is no effluent disposal problem.
  • Reduced stocks of zinc are required. Working capital is not tied up in a molten zinc bath.
  • Fuel is not needed to keep zinc molten when the process is not working.
  • Metal spraying restores corrosion protection on damaged areas of welded galvanised steel (International Standards exist covering this).
  • Coating thickness can be varied to provide extra protection in critical areas.
  • The Metal Spray process is not limited to Zinc.
    • Aluminium, Steels, Bronzes etc. can also be applied for a variety of applications.
  • No re-work required from galvanising dross.
  • The Metal Spray coating is porous and therefore the perfect surface to accept paint or powdercoat (that’s if required as it is not necessary).
    • No need to pre–etch etc. 

How Does Metal Spray Compare with Painting?

  • Materials are of consistent quality and purity, no mixing required before application.
  • Materials have an infinite shelf life if stored correctly.
  • Fewer process steps required.
    • This allows simpler quality control and fewer opportunities for error.
  • Sprayed components require no protracted curing or drying times giving superior utilisation to floor space.
  • Sprayed Zinc, Aluminium and their Alloys give effective corrosion resistance and protection immediately.
  • Sprayed metals are more robust than paints and can withstand rougher usage.
  • Even if the sprayed layer is damaged, the sacrificial action prevents corrosion.
  • Metals can be sprayed in a wider range of climatic conditions (temperature and humidity) than paints.
  • The materials used since the early 1900’s have not changed and are still being used today, whereas numerous paint systems have been superseded many times over.

metal-spray-originate

Did you know? Dr Max Ulrich Schoop (pictured above) pioneered metal spraying in the early 1900’s when he, whilst firing pellets out of a toy cannon he had bought for his young son, discovered that molten lead and zinc would stick to almost any surface.

Have more questions? Call us on (07) 3823 1004 or Click Here to email us.

What is Arc Spray?

 

Heat Source

Electric Arc

Material

Wire

Transfer

Compressed Air

Process

Arc spray (sometimes referred to as twin wire arc spray or thermal arc spray) is a process that uses an electric arc to melt wires. Arc spray systems are commonly considered to be easy to operate and to automate and are offered as "push" or "push/pull" systems. A "push" system pushes the wire to the gun, is lighter and easier to use than a "push/pull" gun and is generally used for engineering applications which use hard engineering wires and have a shorter distance from the machine to the gun (5 metres). "Push/pull" systems are used when a longer distance from the gun to the machine is needed and are typical for anti-corrosion jobs that use soft wires (zinc and aluminium). The systems push or pull two wires to the gun to be sprayed. The wires are forced together and form an electric arc, melting the wire. Compressed air passes through a nozzle which atomises the molten metal and sprays it onto the work piece. These wires are interchangeable and can be used as one wire zinc, one wire aluminium for example. The higher the current rating of the system, the higher the spray rate. 

Arc spray is a very good, cost effective method to apply metallic coatings in a very wide range of applications and is one of the most versatile of all of the thermal spray processes.  It is a simple process to provide corrosion protection coatings to steel fabrication or is as easily capable to provide engineering coatings to re-build or change the surface properties of the sprayed objects. Changing between anti-corrosion and engineering wires is quite simple. Coatings of zinc, aluminium, steels, copper, bronze and other materials can be sprayed for corrosion protection, engineering reclamation, surface modification and decoration. Capital costs of arc spraying are typically higher than flame spraying but the running costs are normally lower. The amount of material that can be sprayed is limited by the wire diameter and the available power of the machine but higher spray rates are achievable with arc spray than flame spray.

Arc Spray coatings can be applied to just about anything including Metal, Wood, Polystyrene, Plastic, Glass, Paper, Ceramics, as well as Chocolate (for demonstrative purposes only) and can be used in unlimited artistic applications. Arc Sprayed coatings also provide the ideal surface to receive any top-coating from painting to powder-coating with any available colour! The Arc Spray process is known for its low heat input when spraying. Low heating of the substrate makes arc spray useful when it comes to thermally sensitive substrates. The low heat input also eliminates the risk of component distortion. The below video will help to emphasise this low heat input by showing examples that would lose definition, distort, warp or even melt when subjected to a high temperature.

General Features

 

  • 1.6mm to 4.76mm wire sizes (depending on which model is used).
  • Low power consumption compared to plasma or HVOF.
  • Simple push-button operation.
  • Low heating of the substrate used makes arc spray useful when it comes to thermally sensitive substrates. For example, capacitors and electronic components.
  • A range of porosity levels can be achieved to enable the coating properties to match the application requirements.
  • Arc spray doesn’t require the use of combustion gases or produce a high-energy plasma; meaning that it poses fewer health and safety risks than other thermal spray processes.
  • Arc spray process offers lower cost and high throughput coatings in comparison to the HVOF spraying process.
  • Engineering applications.
  • Anti-corrosion applications.
  • Surface modification applications.
  • Decorative applications.
  • Manual or automatic operation.
  • Robotic operation option available.
  • Push/Pull synchronous drive gives outstanding wire feed reliability of up to 20m.
  • The closed loop current control ensures reliable spray and ease of operation.

Application Examples

Arc Spray Systems can be used in a range of applications including, but not limited to:

Click Here to go back to the Arc Spray Equipment page.

What is Flame Spray?

Heat Source

Gas fuel* and oxygen flame (*commonly propane or acetylene).

Material

Wire or powder (depending on gun).

Transfer

Compressed air (wire flame).

Process

The gas fuel and oxygen are mixed and ignited to produce a flame. The material, either a wire or powder is fed into the flame. For wire flame spray, the material is melted and the compressed air, passing through a spray nozzle atomises the molten metal and sprays it onto the work piece. The larger the wire diameter, the higher the spray rate. As a general principle, the throughput rate of the spray system is linked to the wire diameter, for example, a 1.6mm wire will spray considerably slower than a 4.76mm wire. For powder flame spray, the powder particles (metal or ceramic) are softened in the flame and the speed of the flame gases through the nozzle sprays the softened powder onto the work piece. Flame spray systems are commonly manually operated but it is possible to semi-automate or fully-automate the process if required. Capital costs of flame spraying are typically lower than arc spraying but the running costs are typically higher. The amount of material that can be sprayed by the flame spray process is limited by the size of wire and the material being sprayed.

Flame spraying can be seen as a similar concept to paint spraying. Once the system is connected up, the sprayer operates a valve to start the gases flowing and lights the gas stream. A trigger is then used to start/stop the wire/powder feed into the flame and the coating is deposited in a similar way to spray painting. These systems are used to reclaim surfaces by applying a similar material or give the surface different properties by coating it with a different material. Most metals can have an aluminium coating applied by the flame spray process. This can be for aesthetic, anti-corrosion, conductivity or many other reasons. Zinc can also be applied to most substrates using the flame spray process. This is often to provide galvanic protection of the substrate, but may be for a number of other reasons. 

With flame spraying, you are using the heat that is generated from the combustion of a mixture of oxygen and a fuel gas, commonly oxy/propane or oxy/acetylene. The molten material is atomised and sprayed to build up a coating layer. Propane gas is most commonly used for spraying low melting point materials such as zinc, aluminium and their alloys at high throughput rates. Propane can also be used to spray bronzes, coppers, Babbitt, nickel, tin/zinc and some steels, although optimum throughput rates may not be achieved with these materials. The Metallisation MK73 system uses propane gas.

Acetylene gas is most commonly used for spraying higher melting point materials such as varying grades of steel, nichrome and molybdenum. When spraying with acetylene, parameters can be easily changed that will give different coating properties. For example, molybdenum coatings can be applied as either a soft, strongly adherent bond coating or as a harder top coating, just by changing the ratio’s of gas to oxygen. Similarly, some decorative coatings of copper and bronzes can have their final colour appearance influenced by the spray parameters. As with propane gas, acetylene gas systems can also spray the lower melting point materials of zinc, aluminium and their alloys, but again, not necessarily at their optimum conditions. The Metallisation MK61 system uses acetylene gas. 

General Features

 

  • Engineering applications.
  • Anti-corrosion applications.
  • Wire flame and powder flame models available.
  • Variety of hose lengths to suit each application.
  • Spreader and non-spreader versions to allow detail work or larger areas to be sprayed efficiently.
  • Stop/start version allows operator to stop spraying and leave the flame lit (e.g., whilst inspecting or moving the work piece).
  • Wire sizes 1.6mm to 4.76mm (3/16”) to suit many application and coating requirements (depending on model selection).
  • Manual or automatic operation.
  • Deflected flame spray extension available.
  • Flame/Powder Spray Equipment Trolleys also available.

Application Examples

Please note that some of the applications listed below are relative to particular Flame Spray systems. Contact us if you have any questions.

Typical applications can be broken down into two different categories – anti-corrosion and engineering coatings.

Anti-corrosion coatings are applied to generally protect steelwork from a corrosive atmosphere with the most commonly sprayed materials being zinc, aluminium and their alloys. Common application examples include the spraying of steel bridges, in-situ pipework in petrochemical refineries, street furniture and vehicle chassis’.

Engineering coatings cover a much wider range of applications where the coating could, for example, provide a wear protection surface, a thermal barrier coating or an electrically conductive path. Common applications include spraying steels to build up worn or mis-machined areas on a variety of components, conductive heater elements on carbon fibre wing edges and hard molybdenum coatings on selector forks.

Flame Spray Systems can be used in a range of applications including, but not limited to:

Click Here to go back to the Flame Spray Equipment page.

What is HVAF?

Heat Source

Fuel (Liquid or Gas) and Compressed Air Flame

Material

Powder (Metal)

Transfer

Via the Flame

Process

The HVAF metal spray process is characterized by a low combustion temperature (1,960-2,010°C | 3,560-3,650°F), high particle velocities (800 to over 1,000 m/s | 2,625-3,281 ft./sec.), resulting in low-oxidized, ductile, non-porous, high-bond carbide and metal coatings. With a spray rate up to 550 g/min (73 lbs./hr), it makes the process much faster, providing a significant advantage over HVOF.

Kermetico HVAF equipment uses the energy of gas combustion in air to spray powders. The combustion temperature in a HVAF gun is typically 1,000°C (1,830°F) lower than that in a HVOF coating system.

The Adiabatic Combustion Temperature of Fuels in Oxygen and Air (a=1, 20°C, 1 Bar)

This lower tempe­rature is ideal for the gradual heating of the feedstock particles of metals and cemented carbides to or slightly above the metal’s melting temperature. The initial oxygen content in the combustion gas mixture is 5-fold lower in our HVAF process compared to any HVOF coating process. Both factors prevent the oxidation of metals and the decomposition of carbides.

Features

  • Environmentally Friendly - High Velocity Air Fuel (HVAF) technology has been shown to be very competitive as an environmentally friendly alternative to electrolytic hard chromium (EHC).
  • Reduced Production Costs - The ecological aspects and shorter processing time reduce processing costs.
  • Thicker Coatings - An option to apply thicker layers provides a way to repair heavily worn components.
  • Higher Wear & Corrosion Resistance - HVAF carbide coatings are also superior to conventional HVOF counterparts regarding wear resistance, corrosion protection and production cost. The high velocity of our HVAF in-flight particles (higher than 1,000 m/s | 3,300 ft./sec.) ) enables the production of very dense coatings.
  • Minimal Elemental Depletion -  the low combustion spraying temperature (1,960-2,010°C | 3,560-3,650°F) and gentle particle heating lead to minimal feedstock phase transformation and almost nonexistent elemental depletion/decomposition of the in-flight particles.
  • Reduce Oxide - Higher Performance Coatings - the replacement of pure oxygen necessary for HVOF with air in our HVAF process significantly reduces the oxide content of the coatings, which is desirable for high-performance coatings.

Applications

 

Cost Comparison of HVOF and HVAF Tungsten Carbide Coatings

HVAF and HVOF equipment investment costs are about the same if we speak of a one system installation. But the Kermetico HVAF system deposits coatings 4-5 times faster (15-33 kg/hour for Kermetico HVAF as compared to 4-5 kg for HVOF), which means you could use one Kermetico HVAF system instead of several HVOF coating systems.

What if you don’t have a large volume, but you do have high diversity?

The Kermetico HVAF AK line is an all-in-one system operating several specific guns: Universal, big OD, small OD, ID, rotating ID and hand-held. This requires less investment in a Kermetico HVAF system and makes the payback period shorter.

The key factors of the cost advantage of Kermetico HVAF technology:

  • Kermetico's HVAF spray rate is 15-33 kg/hour with a deposition efficiency higher than 50%; fewer work hours means fewer hours to pay for; and with our systems, you need to spray just a fraction of the HVOF spray time.
  • No oxygen in HVAF mode – just compressed air, which costs 10 times less.
  • Easy-to-change specialized guns allow spraying each part in the most efficient way.
  • The cost of consumed spare parts is 1/10 of the conventional HVOF expenses for the same work.

The result?

From this, you can see that one hour of Kermetico HVAF costs 30-40% less than one hour of HVOF spraying.

Let’s look at the cost per 5 kg (11 lbs.) of tungsten carbide coating HVOF or HVAF deposited.

 

HVOF vs HVAF Tungsten Carbide Coating Quality-Cost Analysis

Each kilogram of Kermetico HVAF deposited coating is up to two times less expensive than HVOF. Numerous academic and practical research studies that have been conducted at different universities and job shops around the world support these data. We can send you our calculations by request to recalculate with your in-house data.

Coating Materials

The Kermetico HVAF process lets you spray well-known materials with more desirable properties: higher hardness, ductility and deposition efficiency, with lower porosity and cost.

Click Here for more information.

Set Up Requirements

The set up requirements for particular aspects of the HVAF and HVOF equipment are available by Clicking Here.

Is it Worthwhile to Upgrade from HVOF to HVAF?

Your investment in a new Kermetico HVAF system will pay itself back while you are spraying your second metric ton of WCCoCr.

Kermetico offer a Convertible System used for both HVOF and HVAF coatings. It is the technological breakthrough that allows using the best properties of both technologies. You do not need to choose between HVAF and HVOF anymore. Spray with oxygen when you need higher temperature or without it when you need lower oxygen content in the coating. Easy and efficient.

  • You need to buy just the Kermetico HVAF system; it fits all existing HVOF infrastructure (Well, you will probably need to upgrade a compressor if you have a really weak one).
  • Your learning curve will be just a couple of weeks long – our HVAF systems are easy to use for operators familiar with HVOF.
  • You gain $160 per deposited kilogram of E-mode HVAF WCCoCr compared to a conventional HVOF version of the same material.
  • You’ll get back $160,000 per metric ton of tungsten carbide deposited – more than enough to cover all of your expenses.

And some additional benefits come with using Kermetico HVAF as well:

  • You can eliminate the blasting room – blast and spray with one setup to improve quality, shorten manufacturing time and reduce blast media consumption by a factor of 100.
  • User thinner as-sprayed coating thicknesses and minimize grinding time due to the low roughness of the as-sprayed HVAF coating.

For more on HVAF vs HVOF coatings, Click Here.

Click Here to go to the HVAF Equipment Page

Spraying Internal Diameters

The Kermetico HVAF AK-ID system is ideal for lining inside diameters of pipes, tubes, barrels, and cylinder bores which can be effectively rotated.

Click Here for more information.

Hard Chrome Replacement

Kermetico HVAF technology and equipment provide a way for hard chrome replacement with impermeable, hard and ductile coatings that are inexpensive and easy to apply. Numerous researchers have pointed out that HVAF coatings work several times longer than electrolytic hard chrome does having the same or lower cost.

Click Here for more information.

Grit Blasting

The standalone HVAF High-Pressure Hot Blasting Grit Feeder is designed to feed Kermetico HVAF guns with grit media. When using a HVAF gun for grit blasting, grit particles are accelerated to extremely high velocity and simultaneously heated to over 1,200oC (2,200oF), dramatically improving cleaning and profiling efficiency of the process.

Click Here for more information.

If you have questions on the HVAF/HVOF process, please call 07 3823 1004, or email us using our contact form.  

Click to Watch Applications of HVAF Spraying  

What is HVOF?

 

Heat Source

Fuel (Liquid or Gas) and Oxygen Flame

Material

Powder (Metal)

Transfer

Via the Flame

Process

The Hypersonic Spray Process / High Velocity Oxygen Fuel (HVOF) is a process to apply very dense, strongly adhered coatings. A fuel (commonly kerosene or hydrogen) is mixed with oxygen and ignited in combustion chamber. The combustion gases are accelerated through a nozzle. Powder is introduced into the gas stream where it softens and gathers speed before coating onto the sprayed surface. These coatings are commonly used as a hard chrome replacement process and produce very dense, hard wearing coatings. Metallisation offer two variants of HVOF Pistol Control Consoles to operate either liquid fuel or gas fuel pistols. 

The gas stream heats and accelerates the powder particles to around twice the speed of sound, simultaneously softening them. They impact onto the sprayed surface with tremendous energy to form a very dense, strongly adhered coating. 

There is always a demand for more wear and corrosion resistant surfaces and for these reasons High Velocity Oxygen Fuel (HVOF) spray systems are becoming increasingly popular. Unlike the other methods of metal spraying, where the feed stock is melted and projected onto the substrate, the HVOF process simply softens the powder before projecting it. This is because less heat is imparted to the particles and the dwell times are very short, oxidation and decomposition are minimal in a HVOF coating. The main difference which provides the superior quality, is offered by the use of a combustion chamber and accelerating nozzles that produce very fast (approx 1500m/sec) particle velocity that results in high impact energy and hence reduced porosity levels as when compared with other metal spray processes.

HVOF Flame with shock diamonds producing the necessary speed for high impact deposits.


The use of low level porosity coatings combined with hard wearing, corrosion resistant, conductive and high bond strengths allow the process to be used in many applications for a variety of industries including Paper, Pump, Aerospace, Mining and Oil.

The coating density for most metallic coatings will be more than 99.5% of the theoretical density, micro-hardness in excess of 1300 HV300 are commonplace and the bond strengths are beyond the normal values measurable by the ASTM 633 test.

Features

High Velocity coatings produce not only harder, denser carbide coatings, but are also more ductile. Due to the lowered particle temperature there is less shrinkage and this combined with a simultaneous peening effect as the next particle arrives, produces lower residual stresses and enables a much greater thickness to be applied. These properties make the coatings significantly more wear resistant, especially where loads are high or erosion is prevalent. Normal Plasma type coatings usually  fail due to the break up of the coating and not through wear of the particles. A resistant barrier layer provides the corrosion resistance of the alloy materials, hence the reason why coating density is so important. High Velocity Systems ensure there is no degradation. 

HVOF coatings can apply materials that include Tungsten Carbide which makes coatings with exceptional wear protection – up to 10 times greater than hard-chrome plating for example. The process lends itself to high value applications, significantly extending the life of components such as mud rotors, gate and ball valves in the oil/gas sector or hard chrome replacement of aircraft landing gear or hydraulic pistons. 

  • Retention of powder chemistry due to the reduced time at temperature.
  • There is lower oxide content due to there being less in-flight exposure time.
  • There is higher density (lower porosity) due to there being greater particle impact velocities.
  • Improved corrosion protection due to there being less through-thickness porosity.

Benefits of HVOF with Typical Coatings

  • Tungsten Carbide - If this material is overheated, not only does it oxidise and lose carbide to carbon dioxide, but the carbide also becomes dissolved with in the Cobalt Matrix. The resultant mixed Tungsten/Cobalt Carbides are hard, but brittle.  In some circumstances this is not very important, for example, when impact loads are low and wear is by stress abrasion. On the other hand, in applications such as tool and die parts and compressor blades subject to hammer wear, ductility as well as harness is required.
  • MCrALY’s - are a family of high temperature oxidation resistant alloys which are used in gas turbines. They offer protection by readily forming an adherent oxide film on their surface, which delays further oxidation.  However, this readiness to form oxides means that normally coatings will contain oxidised particles. Research has shown that these oxide layers around the particles act as a path for further oxidation and penetration of the oxidising medium to the substrate. The lower the oxide contents of the coating, the better. Oxidation rates follow a parabolic law. In other words, if the temperature is doubled the oxidation rate goes up by four times.  Thus, if the particle temperature can be kept lower the oxide content is significantly reduced. 
  • Corrosion Resistant Alloys, e.g. Inconel 625 - These alloys provide corrosion protection by providing a resistant barrier layer. Therefore, coating density is very important and once again, oxide layers form paths along which the corrosion medium can migrate. Therefore, once again, a low temperature, high velocity process is appropriate. 

Applications

As would be expected from such a coating system, the applications are wide and varied:

  • Agitator Paddles.
  • Aircraft Landing Gear.
  • Aluminium can be Sprayed Very Densely.
    Coatings of 7mm have been achieved and subsequently finely machined.
  • Ball Valves Reconditioning.
  • Calendar Rolls.
  • Compressor Repair.
  • Corrugated Paper Rolls.
  • Crankshafts Refurbishment.
  • Damaged Shaft Repair.
  • Francis Runners - Wear Resistant Coatings.
  • Gas Turbine Compressor Seals and Automotive.
     Turbochargers benefit from the application of an Aluminium/Polyester Powder Blend applied by the High Velocity Process.
  • Hard Chrome Plating Replacement.
    For many years, hard chromium plating has been widely used in fluid handling and hydraulic applications. It has been proven to give adequate wear resistance in many cases and to provide an appropriate surface against which fluids may run.  However, many situations exist where performance can be radically improved, whether in terms of pure wear or in combination with corrosion resistance. Thermally sprayed coatings are available in such a wide selection of materials and to such quality as to be able to exceed the requirements of almost any hard chrome application. The health and safety aspects of plating with hexavalent chromium have also been an increasing cause for concern.  So much so, that some institutions intend to ban its use entirely. Thermally sprayed coatings do not produce effluent that is difficult to dispose of and the plant involved does not contain thousands of litres of toxic chemicals. It is also an ‘in-line’ process rather than a batch process so that material is only used or stocked during production. A further point worth noting is that the size of component for thermal spraying is not limited by the size of the otherwise plating bath.
  • Hard Surfacing.
  • Hydraulic Cylinders.
  • Incinerator Firewalls are Protected from Corrosion.
    At medium temperature by coatings of Inconel 625 and super-heated tubes by Chromium Carbide in a Nickel based matrix.
  • Kaplan Turbine Blades.
  • Mining Truck Front Strut and Wheel Spindle Reclamation.
  • Other Plating Operations can also be Replaced. 
    Copper can be sprayed for inking rolls in the Printing Industry as well as providing excellent electrical conductivity properties for a variety of applications (for example).
  • Pelton Runners.
  • Piston Rider Bands.
  • Piston Rods.
  • Pump Components.
    Either as OEM or repair can be given enhanced lifetime and improved performance using a Nickel/Chrome/Iron/Molybdenum.
  • Pump Rotors.
  • Sludge Dryer Cylinders.
  • Turbine Shaft Repair.
  • Valves and Pumps Subject to Erosive Wear.
    From particles such as sand or ash etc can be protected using Tungsten Carbide/Cobalt/Chromium materials resistant to both wear and corrosion and in special circumstances Stellite 6 can be sprayed as a replacement of a weld clad overlay.
  • Wear Resistance.

As more and more Engineers become aware of availability and capability of High Velocity Systems then the applications for the process will surely grow well beyond its existing market. Our video presentation below demonstrates the Hipo Jet 2700 HVOF system coating a pipe using MSSA HV 40/60. 

For more information on our equipment or consumables, call us on 07 3823 1004, or email us using our contact form.

HVOF Spray Equipment

HVOF Powder Consumables

What is Laser Cladding?

Heat Source

High Power Laser Beam

Material

Powder (Metal)

Transfer

Via Laser Beam

Process

Laser Cladding is a welding process which uses a precisely focused laser beam to generate a melt pool on a component surface. A metallic feed material is simultaneously injected into the melt pool and fully melted to build up a deposit. The feed material usually takes the form of a metallic powder but can also be a wire.

The precise nature of the process allows the quality of the coating to be accurately controlled. The key to successful laser cladding is controlling the heat input into the base material, which can be minimised whilst maintaining a high strength metallurgical bond.

The very fast cooling rate associated with laser cladding has the effect of producing fine high strength microstructures with minimal effect on the mechanical properties of the base material. Numerous coating materials can be applied, the composition of which can be designed to combat the service conditions of the component to be clad.

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 coaxially 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 MET-CLAD 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.

General Features

  • Fully dense, high quality coatings with low dilution.
  • Mass flow control of process and powder feed gases = repeatability.
  • Easy to use, intuitive operator interface.
  • 3kW diode laser – suitable for most cladding operations.
  • PC control with touch screen.
  • Recipes or manual parameter setting.
  • Manual or automatic operation.
  • Ability to cost effectively apply thin welded coatings. ~ 0.5 – 5 mm.
  • Achieve correct chemistry in a single pass due to low dilution.
  • Huge range of available cladding materials.
  • Can clad onto traditionally “unweldable” materials and components due to very small heat affected zones.
  • Minimal distortion due to very low heat input.
  • Very accurate and repeatable.
  • Excellent surface finish.
  • Easily automated.

Applications

Laser Cladding Systems can be used in a range of applications including, but not limited to:

  • Aerospace turbine blades and repair.
  • Aggregate Recycling Equipment.
  • Agricultural components.
  • Ball Valves.
  • Bearing journal repair.
  • Boiler tubes.
  • Cast Iron Repair.
  • Coal and ore crushing hammers / wear plates / sand valves (WC/Ni).
  • Continuous Caster Rolls.
  • Critical component repair.
  • Down hole stabilisers (WC/Ni).
  • Engine parts reconditioning.
  • Fan shaft journals and seal areas (cement industry).
  • Hard chrome replacement.
  • High temp process rolls, hardness & corrosion resistance, valve lips and seats (Cobalt 6).
  • Materials processing hammers.
  • Piston ring groove rebuilds.
  • Pump impellers.
  • Trailer hitch balls.
  • Turbocharger Impellers.
  • Valve balls/seats, process rolls, waste incineration boiler parts, oil refinery process plant (NiCrMo).
  • Valve balls/seats, process rolls, boiler components, waste incineration boiler parts, hydraulic rods, down hole stabilisers (FeCrB).
  • Water pump components.

Click Here to go back to the Laser Equipment page.

What is Laser Hardening?

Heat Source

High Power Laser Beam

Material

Powder (Metal)

Transfer

Via Laser Beam

Process

Laser Hardening is a heat treatment process which uses a high power laser beam to locally harden the surface of steel or cast iron components. Being similar to induction hardening, laser hardening relies on the thermal mass of the component to quench the area to be treated. There is no need for quenching in water or oil to achieve the hardness you require.

Lasers tend to produce harder surfaces to a shallower depth compared to other hardening processes. This makes laser hardening ideal for improving the performance of intricate and high accuracy components.

Important considerations for laser hardening are:

Substrate Material

Only materials which undergo transformation hardening can be hardened by this method, carbon steels, high carbon stainless steels, cast irons and aluminium bronzes are typically considered hardenable.

Surface Finish

The absorption of the laser light into the substrate must be accurately controlled, the surface roughness and finish can dramatically influence the amount of laser energy which is reflected, therefore extremely reflective surfaces are very difficult to laser harden.

Depth of Hardness

Laser hardening can be used to produce a hardened layer up to 1.5 mm into the base material. In general, deeper hardening results in lower hardnesses.

Impact and Toughness

Laser hardening is capable of producing extremely hard microstructures sometimes over 1000 Hv, with this comes loss in ductility if your application demands high levels of toughness then perhaps laser cladding is a more suitable option.

General Features

 

  • One major advantage of laser hardening is that it does not affect the surface finish of the component.
    • This means laser hardening can be conducted on finish machined components, without the need to re-machine afterwards.
  • Laser hardening can be completed with the same MET-CLAD Laser Cladding System used for cladding.
  • The depth and magnitude of hardening can be varied, a depth of about 1.5 mm from the surface is quite normal
  • Laser Hardening relies on the bulk of the component to rapidly draw heat away from the surface. Therefore any component must be of a sufficient size for the quenching process to be successful. As a guide the component should be at least 5 mm thick for optimum results.
  • The surface finish and reflectivity of the component must be clean and consistent in order for the hardening depth and quality to be consistent. Generally a good machined or ground finish is acceptable.

Applications

Laser Hardening Systems can be used in a range of applications including, but not limited to:

  • Automotive dies.
  • Cast iron pistons.
  • Chain-wheels.
  • Cog-wheels.
  • Crane wheels.
  • Edges of blanking dies.
  • Edges of pressing dies.
  • Edges of cams.
  • Edges of gears.
  • Laser cladding.
  • Plastic injection moulds.
  • Sealer rollers.
  • Steam turbine blades.
  • Water pump components.

Click Here to go back to the Laser Equipment page.

What is Plasma Spray?

Heat Source

Plasma Arc

Material

Powder (Ceramic, Metal, Plastics)

Transfer

Via Plasma Jet

Process

Plasma sprayed coatings are used for dense, quality coatings like ceramics, cermets, metallic coatings, WC-Co and meet aerospace standards.

Plasma is the term used to describe gas which has been raised to such a high temperature that it ionises and becomes electrically conductive. In the case of Plasma spraying, the plasma is created by an electric arc burning within the nozzle of a plasma gun and the arc gas is formed into a plasma jet as it emerges from the nozzle. Powder particles are injected into this jet where they soften and then strike the surface at high velocity to produce a strongly adherent coating. Metallisation offer a Pistol Control Console Plasma Spray System, capable of spraying with a range of commonly available plasma pistols, as well as their own PS50 Pistol.

The plasma spray process uses an arc between two non-consumable electrodes to provide a plasma gas stream. Typically a powder feedstock is introduced into this plasma gas stream to heat the particles and propel them onto a surface to form a coating. APS is atmospheric plasma spray; plasma spray deposition carried out under standard atmospheric conditions. Chrome oxide can be deposited by the plasma spray process. It is commonly deposited onto printing rollers where the print pattern is laser etched into the surface of the chrome oxide.

Features

 

  • Mass flow control of primary, secondary and carrier gases = repeatability.
  • Easy to use, intuitive operator interface.
  • Inverter power supply = stability.
  • PC control with touch screen operator interface.
  • Optional keyboard control or operator interface unit.
  • Manual or fully sequenced start-up, operation and shut-down.
  • Various straight, angled and extension pistols can be used.
  • Safety interlocks to prevent running without coolant and gases.
  • Argon or Nitrogen primary and Nitrogen, Helium or Hydrogen secondary gases.
  • Unlimited recipes and parameter recording.
  • Other powder feeders/power sources can be interfaced.

Application Examples

Plasma Spray Systems can be used in a range of applications including, but not limited to:

Flashback to 2001 and the PS50M Plasma system – Metallisation’s first mass flow controlled Plasma system for the ultimate in plasma accuracy.

Click Here to go back to the Plasma Spray Equipment page.

Is this new technology?

No, the Metal Spray process has been in existence since the early 1900’s and is used in numerous applications all around the world. Check out our Industry Applications for more information.

Dr Max Ulrich Schoop (pictured above) pioneered metal spraying in the early 1900’s when he, whilst firing pellets out of a toy cannon he had bought for his young son, discovered that molten lead and zinc would stick to almost any surface.

How does Metal spray / Thermal spray compare with Galvanising?

The process of Metal Spraying/Thermal Spray/Spray Galvanising refers to the same process which has been in existence since the early 1900’s and is a process used worldwide.

The Metal Spray process involves the melting of a wire and projecting it onto the work piece in order to provide a coating that can be tailored to suit the environment into which the component will be located.

How does Metal Spraying compare with Galvanising?

  • Low heat input during spraying eliminates the risk of component distortion.
  • There is no limit to the size of component to be treated.
  • Components can be treated on site, meaning there are no transport or waiting issues.
  • Metal spraying is used to restore corrosion protection on damaged areas of welded galvanised steel and International Standards exist covering this.
  • Coating thickness can be varied from area to area to provide extra protection in critical areas.
  • The Metal Spray process is not limited to Zinc as Aluminium, Steels, Bronzes etc. can also be applied for a variety of applications.
  • No re-work required from galvanising dross.
  • The Metal Spray coating is porous and therefore the perfect surface to accept paint or powder coat (if required as it is not necessary).
    • No need to pre–etch etc.
Does Metal Spray use solvents?

No solvents or chemicals are used, just pure metal. The process only uses a heat source through which a powder or wire is fed, melted and projected onto the substrate.

How does Metal Spray compare with Welding?

Metal Spraying Offers the Following Advantages:

  • Low pre-heat or no pre-heating required.
  • No heat treatment is necessary after coating.
  • Little heat is transferred to the substrate during coating.
    • No risk of thermal distortion.
  • There is little risk of metallurgical degradation of the substrate.
  • Almost any substrate can be coated.
  • There is no dilution of the coating by the substrate material.
  • A wider range of coatings can be applied.
  • Operator skill requirements are lower.
  • Spraying is usually (but not always) faster.
  • Better control over deposit thickness.
  • Machining allowances are reduced, thus saving material.
  • Machining times will also be reduced.
Do I have to paint / powder coat the coating afterwards?

No, it is not necessary to paint or powder coat the coating afterwards. However, in doing so, when correctly applied, it can enhance the life of the coating further. As the colours of Metal Sprayed coatings are limited, a paint or powder coat layer on top of the Metal Sprayed layer is often used for decorative purposes.

Zinc Metal Sprayed Artwork with Paint Top Coat - Image provided courtesy of Ironic Art, Gatton QLD.

How does Metal spray compare with painting?

Metal Spraying Offers the Following Advantages Over Painting:

  • Materials are of consistent quality and purity, no mixing required before application.
  • Materials have an infinite shelf life if stored correctly.
  • Fewer process steps required. This allows simpler quality control and fewer opportunities for error.
  • Sprayed components require no protracted curing or drying times giving superior utilisation to floor space.
  • Sprayed Zinc, Aluminium and their Alloys give effective corrosion resistance and protection immediately.
  • Sprayed metals are more robust than paints and can withstand rougher usage.
  • Even if the sprayed layer is damaged, the sacrificial action prevents corrosion.
  • Metals can be sprayed in a wider range of climatic conditions (temperature and humidity) than paints.
  • The materials used since the early 1900’s have not changed they are still in existence today, whereas numerous paint systems have been superseded many times over.
How does Metal spray compare with electroplating?

Benefits of Metal Spraying Over Electroplating:

  • Adhesion is usually better
  • Non-metallic surfaces can be treated
  • Engineering alloys can be applied as coatings
  • Thicker deposits can be applied
  • There is no risk of Hydrogen embrittlement
  • Deposition rates are higher
  • There is no component limitation size
  • Coatings can be applied on site
  • There is no effluent disposal problem
  • Complex chemical control techniques are not required.
Can I use Metal spray on site applications also?

Yes, the Flame, Arc and HVOF processes can all be operated on site as they are available in mobile forms. For any on-site scenarios, the same standards of Health & Safety procedures need to be applied after undertaking a site risk assessment.

Do International Standards exist?

Yes, over the years the Metal Spray Industry has developed International Standards (ISO) as well as regional standards based on the International ones. The standards cover such things as:

  • Technical supply conditions for wires, rods, cords and powders
  • Approval testing procedures for sprayers
  • Acceptance Inspection of equipment
  • Protective coating procedures
  • Design of articles to be metal sprayed
  • Quality requirements for sprayed structures and more
How do I prepare the surface ready for Metal spraying?

If you are applying an anti-corrosive coating of Zinc, Aluminium or one of their alloys to a substrate, the surface would need to be clean and dry and then grit-blasted. If an engineering coating is being applied, the component should be de-greased and  pre-machined normally by turning a rough thread.

If the component has been in service and/or running in oil, pre-heating the component to between 260°C and 370°C and maintaining this temperature until oil ceases to come to the surface (or until all smoking stops) will satisfactorily clean the component.

Can I use sand to blast the component?

No, the media to be used for surface preparation should be:

  • Metallic Grit - Normally Angular Chilled Iron.
  • Non-Metallic Grit – Aluminium Oxide.
  • On-Site Blasting – Garnet or Copper Slag.
What coating thickness can I apply?

Generally speaking there is no limit. However, from a practical point of view, excessive coating thickness is unnecessary. In some cases the coating thickness may be determined from standards that will give life expectancy until first maintenance, in other cases it can be the requirement necessary to restore a part to its original condition. Metal Spraying allows the coating thickness to be varied to provide extra protection in critical areas.

If I apply an anti-corrosive coating, what guarantees can I give my customer?

The International Standard BS EN ISO 2063 as well as AS/NZ 2312 gives recommendations of coating thickness and time until first maintenance.

In North America, the Metal Spray process is known as “Metallizing” or “Thermal Spray”, with early work being carried out by the American Welding Society (AWS) who in 1953 exposed panels coated with flame sprayed zinc and aluminium and various sealers. Very favourable results were reported after 19, 34 and 44 years of exposure at coastal and industrial sites. This work was followed up by the US Army Corps of Engineers with successful trials of Metal Spray as a more abrasion resistant coating than vinyl on dam gates, and which resulted in a comprehensive design manual (USACE, 1999) which is available on the internet.

The US Federal Highway Agency noted (FHWA 1997) that work by the AWS and US Navy showed that “properly applied metallized coatings (zinc, 85% Zinc/15% Aluminium, and Aluminium) of at least 6 mils thickness provide at least 20 years of maintenance free corrosion protection in wet, salt-rich environments and are expected to provide 30 years of protection in most bridge exposure environments”. The FHWA has sponsored several research projects coating steel bridge beams with TSM, including one of environmentally acceptable materials which found that the thermal sprayed zinc (TSZ) systems were the best performing over 40 coating systems tested (which included top coated and single coat “high-ratio” and other inorganic zinc silicates) with no undercutting at scribe marks after 6.5 years exposure, and had the lowest life cycle cost.

Thermal Sprayed Aluminium (TSA) has been widely used in offshore oil and gas industry and by 1997 over 400,000 sq. metres of TSA had been applied to oil platforms in the North Sea to provide corrosion protection to flare stacks, riser pipes in the splash zone and submerged tethered legs (e.g. Conoco’s Hutton platform built in 1984). Experience indicated that TSA coatings, when properly applied and with the use of specific sealer systems, will provide a service life in excess of 30 years with zero maintenance required.

In short, the years of testing and results which have accumulated into the various standards demonstrate the coatings ability to withstand the harshest of environments and to with stand the test of time.