Restore Dimensions

Worn components can be extremely costly in a production environment where downtime needs to be kept to a minimum. Components/parts can however be salvaged using the Metal Spray process by restoring/rebuilding the dimensions of the damaged part, which in turn can reduce costs. Having to source and then pay for costly replacement parts is then avoided as well as long waits for delivery! Well selected coatings often perform better than a new component. 

Typical applications include reclamation of large new shafts slightly mis-machined during manufacture, replacement of tolerances in shell bearing housings worn as a result of fretting, machine shafts and spindles, rotating and reciprocating shafts, automotive and machine crankshafts, roller faces and journals, cylinder blocks, hydraulic rams, pump plungers and many more!

Hard-facing is commonly used to prolong the life of earth-moving equipment as well as being used to repair equipment components. By applying a harder material on top of the parent metal, it extends the life of the component which in turn saves maintenance costs and downtime. For more on Hard-Facing, Click Here.

Front Strut Reclamation

Mining truck suspension system components can be reclaimed with the Metal Spray process.

The below image shows a front strut for the suspension system being reclaimed with the HVOF process.

Wheel Spindle Reclamation

Mining truck wheel spindles can be reclaimed using the HVOF process.

Underground Equipment

The wear and tear on the expensive underground equipment used by the mining industry is very considerable indeed, particularly at the coal face where mammoth automatic cutters have taken over from the miner. 

An example of wear on the machinery is provided by the main drive head shafts of the coal rippers. One end of the shaft carries the drive, and the other end carries the 1.524m (5ft) diameter cutting head which rips into the coal seam at the face. The drive shaft is keyed to accept the cutting head mechanism and it is at this point that the wear is most severe. The photograph shows the size and position of the keyway clearly. Wear takes place around the bearing circumference and particularly at the keyway edges (which carry the full weight and impact shock of the cutting heads). In the metal spraying rectification of these shafts, any wear of the actual keyway is repaired first of all by re-welding and re-cutting to standard size. The surfaces of a number of such shafts have been reclaimed. A deposit of S2 1.5mm (0.060”) thickness has been applied using the Metallisation Arc Spray system. 

Rear Jack Assembly Piston, Hydraulic Motor Piston and Arcing Cylinder Piston Rod

Three examples of components of a Dosco Miner Machine that has been successfully reclaimed using a Metallisation Flame Spray Pistol in the Central Workshops of the NCB at Midlothian,UK. 

From left to right the components are – A rear jack assembly piston, a hydraulic motor piston and an arcing cylinder piston rod. All the components have received a bond coating of followed by a final deposit of either S2 or 80E.

Caterpillar V12 Engine Block Reclamation

Waste Water Pumps

Pump Sleeve as Shown in Service

Industry: Waste Treatment

Product: Rokide®

Material: Rokide® "C" Chrome Oxide Ceramic Spray Rods.

(Left) Worn Sleeve that has been taken Out of Service. (Right) Worn Area to be Repaired with Rokide® "C" Coating.

The treatment of waste water involves pumps operating 24 hours a day under very demanding conditions. The water used to transport abrasive solids is corrosive in nature, making pump maintenance a considerable drain of both time and money. 

The normal mode of failure is leaking from the gland area as a result of wear and corrosion of the shaft. This can be overcome short-term by tightening of the packing gland, but, over time the leak path redevelops, leading to the pump being removed for overhaul. 

One simple solution has led to major reductions in downtime and the associated cost savings by utilising Rokide® "C" (Chrome Oxide) to coat the pump shaft sleeves.

For this application, Rokide® "C" ceramic spray coating was recommended. 

The parts are coated and then finished to a 16 to 17 RMS. The treatment plant where this application took place now has 14 of their 19 pumps coated with Rokide® "C". The first of the Rokide® "C" coated pump sleeves put into operation was still working well through continual use in its fourth year. The plant coat the balance of their pump sleeves when they need to be repaired.

Rokide® "C" Coated Sleeve Installed into Pump Assembly. Sleeve has been Coated and Ground to Achieve Dimensional Fit and Finish.

This application has prevented downtime and pollution control in waste water treatment plants.

Laser Cladding for Critical Component Repair - Duplex Stainless Steel

Laser cladding, a process that falls into the range of hard-facing solutions, can be used to increase corrosion resistance, wear resistance or impact performance of metallic components, using a method of applying a fully dense, metallurgically bonded and virtually pure coating.

Laser cladding can be used across a diverse range of industries. In this instance it was used to repair an EN8 steel drive shaft from a large CNC boring machine. The steel drive shaft had become worn in two bearing areas and was considered ‘unweldable’ by standard methods. Due to the critical dimensions of the shaft, and its relatively small size, it was crucial that distortion had to be controlled.

The Laser cladding process was an ideal solution for the EN8 steel drive shaft, as it produces a coating with a higher level of purity than other traditional welded hard facing processes. Also, the very low heat input, associated with a laser, minimises distortion and results in a refined microstructure.

Materials - Main Deposit: Duplex stainless steel

Method

Preparation: Clean the worn bearing areas with alcohol to remove grease.

Equipment: Metallisation MET-CLAD system

Application of Laser Cladding

The two worn surface areas of the EN8 steel drive shaft were laser clad with duplex stainless steel and machined back to their original dimensions, enabling the shaft to be returned to the CNC boring machine. The laser cladding process utilises a precisely focused high power laser beam to create a tightly controlled weld pool into which a metallic powder is applied. The powder is carried by a stream of inert shielding gas, which is blown coaxially through the laser beam. The highly controllable nature of the laser beam allows fully dense cladding with minimal dilution and a perfect metallurgical bond. Due to the high level of accuracy and control, laser cladding enables the cost effective application of high performance alloys to tackle a wide range of engineering issues. Typical deposition rates are between 60 and 100 g/min around 3-6 kilograms per hour, depending on the material being deposited and the geometry of the work piece.

To apply a laser clad coating the cladding head has to be fed with four key things; a laser beam, process gasses, the metallic powder and cooling water. The Metallisation MET-CLAD laser cladding control console provides integration and control of the complex component parts. The MET-CLAD system is a simple to use control system with touch screen HMI and is based on the Metallisation HVOF and Plasma control concept. Using laser cladding to repair the EN8 steel drive shaft was the ideal solution, as the repair had to be of a high strength due to the load bearing pressure placed on the working component. The chemistry of the shaft was unsuitable for a traditional welding process due to its high carbon content and it was crucial there was absolutely no distortion. Finally, the low heat input associated with a laser clad coating, had a minimal effect on the base material strength.

Conclusion

Laser cladding is capable of producing coatings with a combination of excellent toughness and abrasive wear resistance and is ideal for Critical Component Repair work. In this instance, due to the low heat input in the laser cladding process, the duplex stainless steel and the EN8 steel drive shaft remained intact, without distortion. A critical requirement in this type of project.

Reclamation of Hydraulic Rams (Cylinders)

Reason for use: Repair of worn and damaged rams.

Crane Wire Barrel

During final machining one section of this crane wire barrel was accidentally reduced by 12.5 mm (½”) beyond the required diameter.  It was impossible to reduce the rest of the barrel to the same diameter because of the strength factor. Metal spraying was used to build up the surface of the mis-machined area back to the originally specified diameter.  A continual groove was then machined into the barrel to accept the feed of the wire rope. The Metallisation Arc Spray specification was – a bond coat followed by a build up of S20 to the required thickness, i.e. a 6.25mm (¼”) on the radius. It will be appreciated that the service conditions in which the barrel operates together with the constant squeezing action of the rope places a considerable load on the metal sprayed deposit; the surface has stood up to the treatment in a perfectly satisfactory way.

Electric Motor Armature

This photograph shows an electric motor armature reclaimed on the journal area. The work was carried out using a Metallisation Arc Spray Unit and a deposit of 2.54mm (0.100”) of S2 was applied. The repair was completed in approximately 36 hours as opposed to a delivery period of several months for a new unit. The cost of reclamation was about 1% of the cost of replacement.

Fork Lift and Earth Mover Brake Drum Clutch Housing

Fork Lift Brake Drum and Earth mover brake drum clutch housing were repaired using a Metallisation Arc Spray system depositing S20 Steel.

Body Panel Repair

Reason for use: Repairing and protecting vehicle body panels.

Metallisation Flame Spray equipment is the preference for classic Volkswagen specialist repairers Vanshack Ltd (UK). The Flame Spray equipment is used for repairing and protecting the vehicle body panels of its customers’ vehicles.

Vanshack provides a range of services including servicing, engine rebuilds, engine re-specification, MOTs, body repairs and customisation to VWV customer’s vehicles and have introduced metal spraying with zinc to their range of services.

Vanshack has chosen the Metallisation MK73 Flame Spray system to metal spray zinc to both the vehicles of VWV customers, as well as other makes of classic vehicle body panels. Vanshack uses the system for vehicle body repair and conservation, using Flame repair for the restoration of peppered panels, Flame fill as a lead loading replacement, Flame seal for seam sealing, Flame coat for anti-corrosion protection and Flame build for component restoration.

Flame Sprayed Zinc

Metal spraying involves the projection of small molten particles onto a blast prepared surface. Upon contact, the particles flatten onto the surface, freeze and mechanically bond, firstly onto the blasted substrate and then onto each other, as the coating thickness is increased. To create the molten particles, a heat source, a spray material and an atomisation/projection method are required.

In the Flame Spray process a wire is fed by a driven roller system through the centre of an oxygen-fuel gas flame where it is melted. An annular air nozzle then applies a jet of high-pressure air, which atomises and projects the molten material (in this case, zinc) onto the vehicle panel surface.

For Vanshack, Flame Spraying zinc onto a peppered body panel is a revolutionary way of restoring and protecting original panels, to ‘conserve the original’. Traditional methods would mean the damage would have to be cut out and replaced but now, using metal spraying, zinc is sprayed over the exposed perforations, replacing what has been lost. In some cases, where the holes are quite large, a support panel or tape is applied behind the open holes to aid the build up of zinc. The zinc will not bond to the support panel or tape, which is simply removed after the repair is complete. The Vanshack Team refers to this as Flame repair.

Body panel before and after Metal Spraying.

Flame Filling is also used by the team, as an alternative to Lead Loading in body filling repair work. This enables car panels to be filled without the risk of heat distortion, which can be created by Lead Loading.

The metal spraying process has made the skills required for Lead Loading much easier, however, this still requires a trained and experienced body repair technician to finish the panel to the highest standards.

In addition, if a panel or section has to be replaced, the team now uses the metal spraying process to load the joins of the panel. A custom coach-works would melt lead into the seam, which is a highly skilled process that can cause heat distortion and is difficult to control in complex and vertical seams.

Seams traditionally would have been sealed using mastic in production cars, which is less robust and more unsightly than metal spraying with zinc. The zinc also offers additional anti corrosion properties, in the repair and seam areas, that are vital to the longevity of the vehicles the Vanshack Team works with. The Vanshack Team refers to this as Flame Seal.

Metal spraying is an excellent alternative to galvanising when spraying entire car panels, Flame Coat provides a good base for the final paint coating to be applied. There are no heat distortion issues, associated with galvanising thin panels, and the coating can be applied in localised areas or over the whole panel. Once the panel has been metal sprayed, Vanshack then applies an appropriate paint coating to the highest standard set by professional coach-works companies.

For more Automotive Metal Spraying applications, Click Here.

Vintage Car Chassis Restoration

Image Provided Courtesy of Metal Spray Hungary

Metal Spray Hungary, in conjunction with a vintage car restoration specialist completed the restoration of a Ferrari Dino sports car which was brought to them in a weathered condition. As the chassis is the most critical part of a vehicle with regards to corrosion, Metallisation Flame Spray equipment was used to provide a high quality, long-lasting anti-corrosion coating.

The process comprised of grit blasting to achieve a maximum surface quality of Sa3 (to remove the contaminants and any residue), which provided a surface roughness for the Metal Spray coating to bind to. The Metal Sprayed coated was then applied, followed by a two component industrial paint system.

Images Provided Courtesy of Metal Spray Hungary

Cast Iron Fencing Restoration

Image Provided Courtesy of Metal Spray Hungary

Metal Spray Hungary completed the restoration of cast iron fencing using Metallisation Flame Spray equipment.

Image Provided Courtesy of Metal Spray Hungary

The surfaces were prepared thoroughly before a 150-300μm aluminium coating was applied to provide an anti-corrosive layer.

Image Provided Courtesy of Metal Spray Hungary

A paint topcoat was then applied to further extend the life of the coating and to provide a decorative finish.

Image Provided Courtesy of Metal Spray Hungary

Architectural Forged Iron Ornaments Restoration

Image Provided Courtesy of Metal Spray Hungary

The restoration work on forged iron ornaments was completed by Metal Spray Hungary.

Image Provided Courtesy of Metal Spray Hungary

The ornaments were more than a century old and had sustained serious marks and damage due to general wear and tear over time, as well as being situated in a C5 corrosion category urban environment saturated by exhaust fumes.

Images Provided Courtesy of Metal Spray Hungary

The damage caused thick layers of rust in some areas, and several layers of paint residue in others.

Image Provided Courtesy of Metal Spray Hungary

As a result, the surfaces were cleaned meticulously to remove the residues and rust. The ornaments were then Metal Sprayed with Aluminium using either a Metallisation Flame Spray or Arc Spray system.

Image Provided Courtesy of Metal Spray Hungary

A primer coat was then applied, followed by a UV resistant topcoat.

Image Provided Courtesy of Metal Spray Hungary

Reverse Engineering

Metal Spray is used in a process called reverse engineering. Reverse engineering is used when no spare parts are available after a component fails or is damaged. Reverse engineering involves working in reverse on the design of an object to achieve the original design information. An example of this could be a classic car part that has corroded or worn over time. In this instance, no spare parts would be available as the parts are no longer made. Using this method enables fast creation of parts which in turn minimises production downtime.  

The Steps of Reverse Engineering

• Inspection of the damaged part.
• 3D scanning of part to achieve original design information.
• Once 3D scanning has produced a CAD model, depending on the size of the component, a 3D printed model may be created prior to manufacturing to ensure a correct fit.
• Component preparation and excess material removal.
• Material replacement using Metal/Thermal Spray.
• Re-machining.

Using one of the Metal Spray processes to repair a damaged part is often a more cost-effective option than purchasing a new part (if they are available) as it shortens the development cycle. Identifying the cause of the damage/corrosion assists in in the identification of a more suitable coating. Metal Spraying will in turn increase the lifespan of the salvaged part to more than what a new part could achieve. 

Gear Reducer Crown Bearing Collars

Gear reducer crown bearing collars are subjected to the Arc Spray process in order to reclaim/rebuild the component. 

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

Metal Spray Equipment