Hard chrome plating, sometimes referred to as functional chrome plating, can be applied in thick layers for heavy industrial applications. It increases wear and corrosion resistance whilst creating a low co-efficient of friction. With abrasion being the most common and destructive wear process found in industry, hard chrome has the potential to solve many problems in pumps, valves, bearings, etc. throughout a wide range of industries; including pharmaceutical, chemical, oil and gas, textiles, printing, food, mining, and countless others.
One application for hard chrome is the refurbishment of worn components where the metal has been lost through wear or been manufactured under size, or, even where there has been an excessive distortion during the hardening process. This application usually requires a thicker deposit and components are pre-chrome ground then a suitable deposit of hard chrome is applied before they are ground back to original sizes and tolerances.
Hard Chrome plating is an electrolytic process utilising a chromic acid-based electrolyte. The component requiring plating becomes the cathode and, with the passage of a DC current via anodes, chromium metal builds on the component surface.
Machine spindles and housings
Pump shafts or rotors
Hydraulic rods and cylinders
Any sliding or rotating shafts
Coating thickness is directly proportional to the parameters dictated by amount of time a component is required to be in the tank and the calculated running current.
Etching is carried in accordance with the guidance relevant to the base material being plated. All components are etched before Hard Chrome plating to provide a good key for the hard chrome deposit to be applied.
Careful jigging is required for hard chrome plating, taking into consideration current carrying capacity and weight of component. Special attention is necessary for the plating of internal surfaces. One of the characteristics of hard chrome is its poor throwing power, therefore auxiliary anodes maybe required at strategic locations.
For high tensile steels, there can be a need for a post-plating heat treatment to eliminate the effect of hydrogen embrittlement which may occur during the plating process.