Prepare the Surface Properly
It is not possible to chrome plate a poor quality substrate and expect the plated coating to last long. All corrosion, fatigue cracks and old coating must be ground out of the ram before it can be chromed plated. 1 mm can be chromed plated over and built up to required thickness. However, pitting of a deeper nature may require metal spraying of the affected area/s before the chrome plating can be re-established.
Specify Deposit Thickness to Suit Clearances
A Hard Chrome Plating deposit is applied oversize to allow for grinding to the required dimension. The thickness of the deposit will need to be specified having knowledge of the bore clearances. 15mm after grinding. It is essential that the final ground dimension is specified at the quoting stage and confirmed with the plater.
Match the Finish to Your Seals
The surface roughness of the chromium plated rod will determine the life of the Hydraulic Rod Seal. A surface roughness that is too rough will cause excessive wear to the seal. On the other hand a surface roughness that is too smooth will cause the seal to run dry. 4 microns for Hydraulic Rod Seals. For more on this, take a look at https://www.poeton.co.uk/advanced-treatments/apticote-100-hard-chrome.
Consider Corrosion Protection for Outdoor Use
Standard chrome is a reasonably corrosion resistant coating. In instances where hydraulic rams are to be used in marine or exposed agricultural environments, a thicker chrome coating or a sealant to protect the chrome could be considered.
Decide When to Replate Rather Than Replace
A hydraulic ram is worth rechroming if the basic steel is sound. If there is any pitting on the rod surface then it would be normal for this to cover less than 20% of the surface area. It is also a good idea to check the straightness of the rod before deciding whether to replace the chrome plate. If the ram is bent then the newly replated seal(s) will not wear evenly. It is often possible to get a simple assessment made of a hydraulic ram for a nominal sum prior to the plating costs being incurred.
A replated hydraulic ram, made with proper clear specifications and an honest assessment of the part’s condition, will perform just as well as a new ram.
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