Heat exchangers are used throughout various industries to transfer heat from one fluid to another. Often, these fluids are corrosive to metal, making it important that components are protected against galvanic chemical damage. In this particular application, the heat exchangers were made of multiple steels including carbon steel, Inconel cladding, and stainless steel – increasing their risk for galvanic corrosion.
The customer required that each bore of the heat exchanger be plated with AeroNikl® 250 for corrosion protection. Each bore measured 19.2mm x 252.5mm (0.75in x 12in) and there were 689 bores per exchanger, with four heat exchangers in total. With an exacting specification to meet, it was impossible to obtain the required thickness of nickel using traditional brush plating techniques. The customer wanted to plate the parts on-site, which meant that tank plating wasn’t suitable either.
With the portability of the SIFCO Process®, SIFCO ASC was able to bring its encapsulated plating system to the customer’s facility to plate the bores on-site. The process required dedicated tooling which was designed to be locked on to each bore. With the tooling locked and sealed, the full process could be completed without changing the electrode. The hydraulic circuit was supplied by a centrifugal pump alternately connected to the electrolyte and rinsing water storage devices. With the setup in place, SIFCO ASC was able to plate two bores per hour with a thickness required of 100 μm (0.0004in), negating the need for the customer to disassemble or remove the heat exchanger from service.