Ellimetal (Meeuwen, Belgium), which manufactures pressure vessels, silos, and specialized process equipment, employs engineering specialists who determine the dimensions and the strength of these structures, taking into account the operational temperatures and pressures as well as wind forces. When working with processes that are subject to erosion, cobalt-based Stellites are commonly used to reduce abrasive wear.
For an industrial refractory reactor project, Ellimetal asked laser cladding specialist Laser Cladding Venture (LCV; Opglabbeek, Belgium) to perform laser cladding on metal parts facing abrasive wear (for example, reactor risers, vapor lines, and air grids). A refractory setup keeps the metal parts processing the refractory away from the ultra high temperatures elsewhere in the reactor. The parts were brought to LCV, where a laser cladding robot applied the abrasive wear-resistant coating.
LCV's laser cladding technology combines an optimum powder formula with dynamic melt pool control. As the robot head moves with uniform speed and standoff, laser cladding is continuously executed with a small melt pool that cools down fast. This results in much lower dilution, establishing the ultrafine LCV Stellite 6 coating microstructure with superior abrasive wear resistance.
Ellimetal recognizes that the hardness of the Stellite 6 coating (50 HRC) compares favorably with conventional hardfacing (39 HRC). The comparison also shows that the cladded surface is much thinner and more uniform, as hardfacing is a semi-automatic process that delivers a roughly 3mm layer with dilution included.
With the collaboration, Ellimetal has concluded that laser cladding and hardfacing are comparable in service cost and duration, and sees potential in proposing laser cladding to its customers.