The technical advantages of Topclad Laser Cladding
Laser cladding is on the rise and is widely accepted as the superior coating (hard plating) that can withstand the most extreme circumstances. The main technical advantages of the laser cladding technique are being explained below.
No failure due to (sub)corrosion, external impacts, bending or thermal shocks
The majority of the hard chrome, nickel-chrome (NiCr) and HVOF coatings fail due to subcorrosion, external impacts, bending or thermal shocks. Once a chrome or HVOF coating fails delamination starts, resulting in a necessary expensive overhaul or substitution. Delamination does not occur with a laser clad layer due to intermetallic bonding, no porosity and high ductility.
Intermetallic bonding
During laser cladding an alloy is being melted with the base material. In other words, there is an intermetallic bonding between the base material and the alloy being laser cladded. So, by its very nature, it is not possible to have subcorrosion between a laser cladded layer and it’s base material. In contrast, HVOF and NiCr coatings are not melted but mechanically glued. Due to pores and cracks seawater, for example, is able to get between these coatings and the base material, start to corrode on the base material and push off the layer from the inside out.
High ductility
The ductility of the Topclad laser clad layer is much higher compared to HVOF and NiCr coatings. This high ductility, combined with the intermetallic bonding, prevents heavy damage due to external impacts (e.g. rocks or tools), bending (e.g. long thin rods) and thermal shocks (e.g. steel production process). The ductility enables the Topclad layers to absorb high material stress and, consequently, avoids cracking. HVOF and NiCr coatings are not ductile at all; bending, external impacts and thermal shocks will inevitable result in cracking.
No porosity
Topclad laser cladded layers have a porosity of 0%, resulting in an impenetrable layer that prevents any corrosive fluid to access the base material, again preventing subcorrosion. This is not the case for HVOF and NiCr coatings that have a porosity of >0.5%.
Excellent repair possibilities
The laser cladding technique provides several cost-efficient and fast repair possibilities without compromising on quality. These repair possibilities significantly increase the lifetime of the cladded component and the uptime of the related equipment.
Overhaul of heavily damaged products
Heavily damaged components can be re-used by applying a Topclad laser clad layer up to several millimeters thick. There is no need to purchase and remanufacture expensive new components. They can be repaired and put back in operation within days instead of months.
Repairability of damaged thread
Heavily damaged thread can be repaired by removing the thread, cladding new material as thick as needed and cutting new thread. Tests have shown that this thread has a higher tensile strength than thread applied in regular carbon steel. Another reason to apply laser cladded Inconel-based thread is the need for easy and smooth removal of threaded parts (e.g. clevis eyes and nuts) without any effort due to corrosion.
Repairability on-site
Moderate damages can be repaired on location without disassembly of the component. Just a standard TIG welding machine and specific welding consumables are needed to fix the job.
