Protect Parts for Sustainable Asphalt Production
BY AsphaltPro Staff
By Martin Kirchgassner
Operators of asphalt plant and paving equipment can reduce maintenance costs and downtime by taking advantage of the latest wear facing technologies. When critical equipment functions optimally, it consumes less energy; therefore, asphalt plants can benefit from both improved energy efficiency and a lower CO2 footprint.
Asphalt production and paving subjects heavy equipment to an abrasive mix of aggregates, binder and filler. Where aggregates used to be mainly crushed rock, sand, gravel or slags, they are now being supplemented or replaced with construction and demolition debris. The main binder used is liquid asphalt cement (AC); however, bio-based binders are also under development. Whatever its constitution, asphalt can cause intensive wear and tear that left unchecked will cause early failure of components. The deterioration of key components will lower energy efficiency and performance. It may also affect the quality of the asphalt, increasing the risk of rejection by the final customer.
Wear facing can help address these challenges by protecting equipment against wear. In addition to extending the life of components, it can help maintain their original shape and dimensions, so they continue to offer optimal performance and energy-efficiency. These treatments can be applied to asphalt processing equipment at any stage, from original manufacture or as part of a repair and restoration process. Not only does wear facing give components a second life, but it often results in better-than-new performance. This article looks at Castodur Diamond Plates® (CDP®) specifically.
Diamond plates for active protection
CDPs are designed to provide the basis for comprehensive and cost-effective wear protection. They feature a composite structure made by arc-welding, vacuum-fusing or laser-powder-coating of abrasion-erosion-resistant alloys onto a weldable steel plate. The production process is based on advanced material science to ensure premium quality and consistent properties across the entire surface.
The hardness value (HV) of the CDP material is 1,500 to 3,000. Its durability owes much to the presence of ultra-hard phases anchored in a robust matrix.
CDP plates can be cut—using standard methods such as plasma arc, water jet or laser—and shaped and fitted to protect almost any surface in an asphalt production plant or to construct components like the tubes for filler transport, chutes, grates and screw flights. Retrofitting the plates to existing equipment is straightforward, with attachment by screws, rivets or spot welding. (It should be noted that the robust nature of asphalt equipment means that it can change shape over its long life. Therefore, to maintain the best possible fit and function, new measurements should be taken each time an engineer returns to check for wear and plan liner replacements.)
Tests have shown that CDP plates can offer up to five times longer service life when compared with previous solutions such as hardened steel, polyurethane and cast iron. They provide a high level of protection for equipment both while asphalt is being mixed and during cleaning and maintenance. In addition, the plates are highly resistant to chipping and are available in different alloys and thicknesses, designed for specific wear scenarios.
Reinforce paving equipment
Wear facing can be usefully applied to asphalt paving equipment such as road scrapers and pavers. On road scrapers, CDP has been used to protect the rail, the rotor and the casing. On pavers, CDP is an ideal solution for lining the chain conveyor. In one example, a chain conveyor liner manufactured from specialized heat-treated steel plate with a Brinell hardness of 400 HB was replaced by CDP. The result was a fivefold increase in component life.
Protective coatings
There are some components where CDP plates may not be suitable due to the nature of the surface that needs to be protected, such as mixer blades or finisher screws. In this case a protective coating may be applied using techniques including wire coating, arc wire spraying and powder coating.
Whatever the maintenance or wear-related challenge in asphalt plant or paving equipment, Castolin Eutectic has a well-proven answer. The aim is to help customers build key components back to better-than-new performance over significantly extended lifetimes. A network of 700 technicians and specialists is ready to provide on-site wear detection, analysis and advice, before recommending the ideal solution. Repairs and wear protection can be applied either at the customer’s own site or in specialized workshops.
Martin Kirchgassner is the chief technology officer of Castolin Eutectic. For more information, visit the company’s website.
To assist asphalt producers with their bottom lines, original equipment manufacturers (OEMs), component manufacturers and service providers are releasing a host of new offerings to the marketplace. Check out a sampling over the next few pages of what’s new to help you with production.
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