Ceramic lined pipes are used to transport highly abrasive media. The Kermetico HVAF process provides a way to improve protection of internal surfaces of pipes and fittings with the tungsten carbide coating.
Tough and ductile tungsten carbide lining provides a higher level of wear and abrasion protection than many legacy lining methods.
Kermetico Inc. designs and manufactures HVAF and HVOF equipment for tungsten carbide lining of carbon steel pipes with a diameter of 80 mm (3.15”) and larger, and provides HVAF and HVOF coating services in California, USA.
A Tungsten Carbide Ceramic Lined Pipe
A Comparison of Methods to Protect Piping from Abrasive Wear
Internal wear from an abrasive material is a cause of concern for many operations that pump tailings, slurries and other abrasive products through a pipeline.
To achieve economic long-term wear protection one needs to consider many factors. The application-based choice depends on the proper selection of the wear resistant pipe linings as well as knowledge of the expected cost.
A wide range of different materials with different characteristics can be chosen to protect against wear. Pipe linings made of mineral, metallic or ceramic materials are used widely.
Tungsten carbide coatings are more wear resistant than many other industrial liners. Numerous researchers have shown that an increase of hardness provides an exponential increase in wear resistance.
The Advantages of Wear Resistant Tungsten Carbide Pipe Lining
- Long lifetime and maintenance-free operation of lined pipes
- Reduced pressure losses and lower energy cost
- No production losses or contamination of the conveyed materials due to abrasion, mixture or oxidation
- No spilled material to clean up
- Smooth surface to achieve good flowability and to avoid plugs
Using Kermetico HVAF Equipment and Technology to Manufacture Abrasion Resistant Ceramic Lined Pipes
Our HVAF equipment is designed to thermal spray tungsten carbide linings inside pipes and fittings.
Prof. Qun Wang has shown in his article “Wear and corrosion performance of WC-10Co-4Cr coatings deposited by different HVOF and HVAF spraying processes” that, “The WC-10Co-4Cr coating deposited by the HVAF spraying process exhibited nearly the same phase composition as its initial feedstock powder, which included mainly the WC and some Co3W3C and crystal Co phases with nearly no decarburization.”
Depositing HVAF Tungsten Carbide Coatings onto Internal Surfaces of Piping Fittings
The Kermetico HVAF AK system may operate several thermal spray guns with different designations:
- AK5 – a compact spray gun to efficiently deposit coatings onto internal surfaces of vessels and complex geometries
- AK-ID – a gun to spray inside diameters 80 mm (3.15”) and larger
- AK-IDR– a rotating gun to spray barrels 100 mm (4”) and larger up to 600 mm (2’) deep
- AK-HH – a manual HVAF gun to spray on-site or onto complex surfaces
The Kermetico HVAF AK5 System Depositing a Coating onto an Internal Surface of a Pipe
The high energy efficiency and relatively low kW output of Kermetico HVAF systems minimize the heat load into the pipe surface, allowing spraying faster and with lower ventilation requirements to maintain an ideal application temperature without overheating the part.
The Quality of HVAF Tungsten Carbide Ceramic Pipe Lining
The Kermetico AK-ID HVAF gun is “a small rocket engine,” generating a jet of spray particles with a velocity that is generally in the range of 650-750 m/sec (2,100-2,500 ft/sec.) Such particles form dense and tough linings.
Our internal diameter metal and carbide linings (WC-10Co-4Cr and Hastelloy-type) are non-permeable to gas and liquid. Our tungsten carbide coating has a hardness of 1,100-1,300 HV300 for small diameters, up to 1,400 HV300 for diameters 255 mm (10”) and larger.
Regardless of the high hardness, these linings are not brittle since both decarburization and oxidation do not occur in our low-temperature HVAF process.
Want to know why?
The combustion temperature in air-fuel mixtures is typically 1,960-2,100°C (3,560-3,650°F) which is about 1,000°C (1,832°F) lower than in oxygen-fuel combustion.
This lower temperature is ideal for the gradual heating of the feedstock particles of cemented carbides to or slightly above the cementing metals’ melting temperature.
The initial oxygen content in the combustion gas mixture is 5-fold lower in our HVAF process compared to any HVOF process. Both factors prevent the oxidation of metals and the decomposition of carbides and their dissolution into the metal binder.
These factors allow the retention of the original ductility of the powder feedstock in the applied coating, even when the hardness of the carbide ceramic layer exceeds 1,400 HV300.
Kermetico HVAF and HVOF Thermal Spray Coating Equipment
Kermetico designs and manufactures HVAF and HVOF thermal spray equipment.
- Convertible HVOF and HVAF equipment:
- C6 – a general purpose HVAF-HVOF gun
- CID – an HVAF & HVOF system for ceramic lining
- Multi-purpose HVAF AK systems, with a range of spray guns:
- AK6 – a universal gun to spray a balanced mix of parts in a job shop
- AK5 – a compact gun to spray smaller parts, thin walls and complex surfaces
- AK-ID – an 80 mm (3.15”) and larger internal diameter spray gun
- AK-IDR – a rotating ID gun to spray 4” (100 mm) and larger bores
- AK-HH – a handheld gun for on-site coating
- Additional equipment:
- An HVAF grit feeder for the grit blast preparation of parts to reduce coating costs
- A Gas Permeability Tester for an instant check of a coating’s through porosity
Kermetico, Inc. – Material Science Excellence, HVAF and HVOF Equipment Manufacturing and Thermal Spray Coating Services Since 2006
We create equipment that helps material scientists, engineers and business managers achieve their goals.
We have installed more than 60 Kermetico HVAF and HVOF systems in the USA, Europe, Japan and China.
Some of the systems are at work in Universities and National Labs, but most of them are used in production thermal spray shops.
We proudly design and produce our thermal spray equipment in California and install it all over the world.
You can visit our R&D center in Benicia to meet our designers and see our HVAF equipment in action.
We also service U.S. customers with HVAF and HVOF thermal spray coatings – ourselves and through the network of our partners.
